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A PROSECUTOR’S GUIDE
TO THE USE OF
This guide for the use of audio taped evidentiary material
has been prepared with emphasis on the different steps
encountered during prosecution of a case, starting with pre-trial
preparation, through jury deliberation.
The recommendations are based upon our experience in
over 1,000 cases in 23 Federal districts, and represent the
common problems and procedures found in all cases involving
audio taped evidentiary material.
Finally, please remember that this guide has been written
by an engineer. Consequently, any legal conclusions should be
taken with a "grain of salt", any legal expertise having been
through courtroom osmosis.
Upon learning from an agent that a case includes tape
recorded evidentiary material, after the initial shock subsides, the
most important part of preparation begins --namely, transcript
The importance of transcript preparation cannot be
underestimated. Upon it rides the following:
1. Ability of thejury to hearthe tape
2. Believability of the conversation
3. Credibility of the witness testifying as to the conversation
4. Believability of the entire prosecution case.
If the work in connection with a tape case were to be split
between pretrial transcript preparation and presentation at trial,
the pretrial transcript preparation phase would merit 99% of the
effort, whereas the trial presentation would merit only 100/6. The
reason is that a well-prepared, accurate transcript will
immeasurably assist the jury (and Court) in hearing noisy or
otherwise inaudible portions of the conversation. An accurate
transcript gives the jury listening to the tape for the first time the
benefit of the hours of work that went into transcript preparation.
The apparent intelligibility of a tape is increased to a point where
the jury can just about hear the desired conversation on their one
and only listening as well as you did on the last playing during
The initial draft of a transcript can be done by a secretary,
or preferably by the undercover participant, or alternately by the
case agent. The undercover participant, presumably the one
through whom the tape will be introduced, is the person who is
best able to make voice identification for transcript preparation.
Also, names, dates, places and slang expressions will be more
recognizable to him than to a transcriber not familiar with the case.
The form of a transcript is as follows, double spaced
like a script from a play
Costello: What's the name of the guy on second base?
Abbott: That's what I said.
Costello: What's his name?
Abbott: That's right.
Some standard abbreviations used in transcripts are:
UNM - unknown male
UNF - unknown female
SCI - special cooperating informant
(UI) or (U)- unintelligible
(IA) or (I)- inaudible
Participants should be designated by their names, to
with the indictment, unless you feel that there is an advantage
in using a particular given name, or if one is continually being
referred to by his first name on the tape.
Pages should be numbered A-i, A-2, A-3, etc., the "A"
designating the first draft.
Parenthetical remarks, such as (Louie dialing telephone)
(sound of spaghetti boiling over), or more seriously (sound of
money being counted) can be inserted, but proceed cautiously,
since there is a strong likelihood that since the transcript will be
used only as a guide for the jury in listening to the tape, everything
other than actual dialogue will be ruled inappropriate by the court.
At the top of the first page, a separate short paragraph
state that for instance:
The following is a transcript of a telephone call
between JOHNNY CARSON and ED Me MAHON on
October 3, 1987, at 6:10 P.M. The call was received on
telephone number (213) 555-1212.
CARSON - Johnny Carson
MC MAHON - Ed McMahon
UNF - unidentified female
The above may or may not be ordered redacted at trial,
it will serve to eliminate confusion in a multiple tape case. For
a simple 20 page transcript, hundreds of pages of drafts,
handwritten, corrected, typed, and re-typed, can be generated,
and it is absolutely necessary not to allow the transcripts
over your office. Runaway transcripts are as deadly as quickstand,
especially on the eve of trial.
Incidentally, one might want to use all capitals for proper
names in the text of the transcript.
Tapes you are likely to encounter are:
Telephone tapes - generally of good quality since the
participants are in effect speaking directly into the tape
Bug tapes - these are of various types, usually with
considerable room echo and transmission noise. These
tapes can vary from low quality unintelligible tapes to high
quality, perfectly legible tapes, depending upon location
of bug, participants and ambient noise.
Body tapes -
NAGRA - a self-contained miniature tape recorder of
extremely high quality (about $7,000) which is about
size of two packs of cigarettes. The NAGRA is capable
of recording conversations as long as 3 hours and 15
MICROCASSETTE - various microcassette recorders are
used in the field due to their small size and consequent
ease in concealment. Quality of microcassettes is inferior
to that of a Nagra, but the cost for a microcassette can
be as low as $50. At the normal slow speed of 1.2 cm./sec.
maximum recording time on a microcassette is either 60
or 90 minutes, depending on the type of tape used.
AID - the AID device is a miniature radio transmitter which
is used primarily because of its size, about 1/2 that of a
NAGRA, and also to protect an undercover operative by
allowing surveillance agents to monitor a situation while
recording at a remote site in a car or in an adjacent
location using an attache case radio receiver and either
cassette or reel type recorder. The quality of the AID is
inferior, as it is subject to all types of radio interference.
The worst tapes that you will hear are AID's, for the above
During subsequent drafts at one point the tape should be
indexed; that is a record should be made of where different
statements in the transcript appear for future reference. One might
include the index counter setting along the left or right margin
in parentheses for at least one or two statements per page on
a transcript to assist in finding selected portions later during
summation or deliberation.
IMPORTANT: Be advised that the index counter on one
machine will generally not agree with one on another machine.
Counters measure arbitrary units, not feet, and vary even from
one end of a tape to the other. Consequently it is a good idea
to mark somewhere the model and number of the machine on
which the indexing is done.
Playback (as well as recording) of tape-recorded evidence
is quite demanding. Reliability of machines is of paramount
importance. Usually undercover agents are not in a position to
have a duplicate conversation with a subject after it is discovered
that a recorder has failed. Similarly in the courtroom the
smoothness and continuity of your presentation is important in
the minds of the Court and jury. For these reasons it is imperative
to use the most reliable machines available. An example of such
a machine is the Phi Tech Desktop Recorder designed for
constant use with a MTBF (mean time between failures) of 3,000
hours. This cassette deck has two speeds, operates in full stereo
and also contains its own speakers for portable use. For
transcription there is an optional remote control and variable speed
With respect to court-ordered Title III telephone taps the
original tapes will be sealed in order to preserve their integrity.
Original quality tapes will be available for review and transcription
however thanks to devices like the Phi Tech Title III Line
Monitoring System. This is a suitcase sized piece of equipment
which connects to the telephone line and produces 3 original
quality tapes simultaneously. Thus a duplicate original,
and a work
copy are made along with an original to be sealed, all automatically
and with the same quality. As with all equipment used in law
enforcement reliability is of paramount importance. The Phi Tech
system is an example of such a unit.
It is not uncommon in the case of long-term conspiracies
to have several hundred pertinent conversations, ready to play
at trial. It is imperative in such a case that a chart be made with
columns set up spreadsheet style, for date, time, original reel or
cassette number, intercept number, and columns to be checked
when final enhanced tape has been produced, draft transcript,
final transcript, transcript interpreted, if necessary, and final review
of tape and transcript by witness. Without such a chart this number
of tapes can easily get out of hand.
Once the final draft is done by the participant, he should
initial both final transcript and original or enhanced tape after
listening while reviewing the draft of the transcript.
In many cases it is desireable to produce enhanced copies
for use at trial. Enhancement is really a misnomer since in actuality
nothing is enhanced. Rather the extraneous noise and nonhuman
sounds are minimized electronically leaving the original speech
more intelligible and easy to understand. The original tape is not
changed in any way during the production of the enhanced copy.
Professional Audio Laboratories specializes in the production of
the dearest enhanced copies possible using the latest state-of-
the-art enhancement equipment. Please call with your
The final draft of the transcript can be numbered without
identifying draft designation, and after a final review by the
witness, all previous copies destroyed. At least 20 copies of the
final draft should now be run with the signed original marked for
i.d. Usually the tape is marked Government's Exhibit 6, for
example, with the transcript marked 6A.
A copy of the tape and a copy of the transcript are now
forwarded to defense for "discovery." If, due to time pressures
you must forward a draft rather than the final transcript, clearly
mark it "Preliminaty Draft" so that you are not bound by it.
At this point during pretrial motions you might request,
respect to the tapes and transcript, that any motions be made
by a specified date so as to leave time for any transcript changes
and reduplication, etc. Hopefully this will preclude defense from
making these motions at trial just before playing.the tapes for the
jury. This will serve to bind defense after the specified date as
to transcript, etc.
If only a portion of the tape is to be played one has
of providing either a transcript of the complete tape in which it
is indicated which parts will be played for the jury, or, alternately,
only a redacted transcript corresponding to the parts to be played.
The defense in this case would be responsible for providing a
full transcript if they desire to play the full tape.
After receiving the copy of the tape and transcript,
defense attorney will either call and say that he hears nothing
on the tape or that your transcript does not agree with the tape.
At this point, a meeting is generally arranged to allow the defense
attorney (and sometimes defendant) to listen to the original tape
at the U.S. Attorney's office and in the custody of a Government
agent. Hopefully some of the discrepancies in the prosecution
and defense transcripts are resolved at this meeting.
If there are any remaining discrepancies, an audibility
hearing is usually scheduled so that the Court may listen and
I.whether or not the tape on the whole is audible
2. the most accurate transcript at questioned parts
Note that some judges prefer to leave the accuracy of the
transcript as a jury issue. Consequently, sometimes at questioned
parts two versions of the transcript are submitted to the jury.
Be advised that Courts do not like to spend hours listening
to tapes in order to decide issues regarding descrepancies in
transcripts. It is clearly better, if possible, to resolve these
discrepancies without the need to involve the Court.
At the audibility hearing, in addition to audibility,
of relevance, custody and authenticity may be raised. These are
handled just as for any other piece of physical evidence. Note
that there are certain scientific tests which can be performed to
verify authenticity, should that be questioned.
If in fact there is a challenge as to authenticity, or an assertion
that the tapes have been 'altered" in some fashion, it may be wise
to employ an expert to examine the tapes and produce a report
as to authenticity, reliability and continuity of questioned tapes.
This is done routinely at P.A.L. In fact from electronic and physical
tests we can determine whether the recorder was portable or A-
C powered, mono or stereo, the order of recordings on a tape,
whether a tape was recorded in the U.S. or in other parts of the
world, and whether there were any erasures, over-recordings or
irregularities of any kind observed. This is often a useful test in
the case where you have tapes recorded by an unsupervised
It is important, as at trial, that tapes be played in
possible manner for the Court, and that the best possible transcript
be presented at this time, since the reaction of the judge in
listening to the tapes for the first and only time will probably be
a guide as to what one might expect in jury reaction.
Assuming that the tapes and transcripts pass the audibility
hearing, the next step is:
Selection of Jurors
During the Voir Dire of jurors a question is usually put forth,
"It is possible that tape recordings, which were made without
the knowledge of all participants, and totally within the scope of
the law, may be introduced into evidence (by the Government).
Do any of you (potential jurors) have any strong feelings, one way
or the other, in connection with the use of such recordings, which
would prevent you from rendering a fair and impartial verdict in
One should also be wary of jurors with hearing aids or
hearing disabilities. Not only might such a potential juror not hear
well, but the use of the tapes might somehow seem offensive or
embarrassing to him.
For best possible playback of tape recorded evidence,
headphones (and processing equipment) are used, as opposed
to loudspeakers. The reason for this is that every room has
different acoustics and hence a tape which was perfectly audible
in your office pretrial will be lost in the acoustics of a large wood-
paneled courtroom. Also, with a speaker system if juror #1 turns
the pages of his transcript or sneezes, juror #7 behind him will
not hear the tape. With headphones, the uniform signal is
delivered to the ears of all jurors independent of physical
conditions of the courtroom. Incidentally, headphones should also
be provided for defense, prosecution, judge, clerks, court reporter,
and witness. The court reporter will probably not even don his
headphones for fear of being asked to take the dialogue as it
comes. This is unreasonable as the number of hours required
to produce the final transcript would attest.
During jury selection, the headphones, tape recorders and
processing equipment, if used, can be sitting out on your table.
This has been known to have two results--first, guilty pleas, or
second, objections by defense counsel.
At any rate, it can be pointed out that it takes quite a while
to set up the courtroom properly, and that the equipment being
set up will save the Court's time.
Once the jury is selected and the trial is proceeding,
eventually the time comes for the introduction of the first tape.
THE PLAVING OF THE TAPE
The witness is asked the following questions:
Do you recognize this tape? (He initialled it.)
How and when was it recorded?
Do you recognize this transcript? (He initialled it.)
Have you had occasion to listen to this tape?
And does it comport with your recollection of the
conversation as it took place?
How did you prepare the transcript?
Have you read along with the transcript as the original
tape was played?
And does it accurately reflect the conversation as it
Do you recognize the voice on the tape?
Did you assign the voice identification of the transcript
from your familiarity with the voices of the participants?
Your Honor, I now offer Government's exhibit 3 and 3A,
the tape and transcript, into evidence.
At this point there will probably be objections, or a request
for a Voir Dire on custody, or voice i.d., etc. Also, in only 3 out
of 100 cases were the transcripts actually accepted into evidence
and later permitted in the jury room during deliberations. They
are usually allowed to be used by the jury as a guide only when
listening to the tapes. A cautionary instruction is usually given
by the Court, instructing the jury that in the case of a discrepancy
between the tape and the transcript, the tape, being the evidence,
During the playing of the tape any press reporters can be
given headsets, or alternately, a small speaker can be set up,
Located a distance from the jury so as to provide a signal for the
spectators, thus countering the defense objections that in its
absence, "this is not a public trial.
If only part of the tape is played by prosecution, the
can play the entire tape. For this reason, complete transcripts
should be available for this eventuality. One would do well to
consider the effect of minor supposedly exculpatory material being
played to the jury by defense versus playing an entire tape and
hearing the witness testify on direct as to the meaning of different
statements on the tape.
With respect to testimony during introduction of tape
recorded evidentiary material, it is important to preserve continuity,
while providing as much insight into the facts of the case for the
jury. Accordingly, a tape might be played in its entirety followed
by a Q & A session with reference to the transcript. This, in
effect,allows the jury to first hear the tape and then while the
transcript is still in front of them (subject to objection),
are reviewed and explained, statement by statement. Alternately,
especially if the tape is lengthy, the tape can be stopped after
each item and the appropriatequestion asked. The condition of
the individual tape will suggest which is the logical presentation.
At the summation one might want, for emphasis, to either
play selected portionsof the recorded evidence for the jury, or,
alternately, to quote from the transcripts. Sometimes, in a long,
multi-tape case, a composite tape is prepared, wherein one quote
after another can be played in the most effective sequence. Also,
at this time one can invite the jury to ask for the tapes during the
deliberations so that they can listen to the words actually spoken
by the defendant. In effect, they can be there at the time of the
Often during the summation the defense will argue about
the meaning of the words, that the defendant was joking, etc.,
points which can be taken up on rebuttal.
During deliberation, the jury will often ask to hear
tapes, or parts of tapes, which were introduced into evidence.
Obviously, th'e tapes and transcripts should be available, ready
for use at this time. Care should be taken to play the tapes in
the dearest possible manner, since the jury obviously has a
question which will be answered one way or the other by replaying
the tape. Sometimes it is to convince a hold-out as to
mind or intent. Sometimes it is to answer a factual question. We
have played and replayed crucial statements as many as
Tape recorded evidence provides you with the means to
present aclear accurate and factual record of events
transpired during the course of a crime. They are effecient,
concise, and ovennrhelming when used "properly". However it
possible to overdose on tapes. One should be cautioned against
using tapes of many, identical transactions once a pattern
been established in a long term conspiracy for instance. We have
had trials where the combined total number of pages of transcripts
exceeded 1000. A jury can become weary after several hours of
listening especially if the quality of the tapes is less than perfect.
For this reason it is desirable to present testimony between tapes
as a breather for your "captive audience.
Foreign Language Tapes
In the case of foreign language tapes the balance of
importance of pretrial versus in courtroom presentation shifts even
more in the direction of pretrial work, since the jury will at best
be listening to a tape which they do not understand, for which
an English transcript has been provided
The procedure to follow in pre-trial preparation is to
the undercover participant listen to the tape and prepare the most
accurate foreign language transcript as in the case of an English
tape. Following his initialing the final transcript, an interpreter
should render the best interpreted English version and sign it.
The final step which seems to work is that a final composite
transcript is prepared in which there are two columns, one for
the English translation which the jury pan follow effortlessly, and
the other for the actual dialogue that' appears on the tape even
if it is partially in English mixed with a foreign language. This
presentation gives a clear picture of exactly what is on the tape,
and also allows you to separate the work of the undercover
participant and the interpreter in preparation of the transcript.
A foreign language tape can be played to allow the jury
hear the emotion or to emphasize state of mind, etc., even though
the actual content is not understood by the jury. Whispering,
yelling and other voice manipulations come across emphasized
when one is not busy listening for content, and so often there
is reason to play foreign language tapes for the jury. In such a
case both the agent and interpreter would testify as to the
procedure used in preparation of the final transcript.
Simultaneously Recorded Tapes
Occasionally you will encounter situations where an agent
utilized a NAGRA (body recorder) and a AID (body transmitter)
simultaneously the result being two independent tapes of the same
event. Usually the NAGRA will be of superior quality and therefore
probably the one used at trial. Sometimes, however, due to
circumstances, one may wish to use both recordings, if, for
instance, some statements are more audible on one tape and
others more audible on the other. In such a case independent
transcripts should be made for each tape leaving spaces and
(UNINTELLIGIBLE) where there are spaces even though you
know from the other tape what was actually said at that point in
the conversation. The reason is that the transcript is supposed
to reflect the tape and is to be used as a guide only during the
presentation in court of the actual evidence. There is also the
possibility that for one reason or another the other tape will not
be admitted into evidence. Each tape and corresponding transcript
must be able to pass into evidence on its own merits without
extraneous information. Usually playing the better quality tape
coupled with pertinent testimony is sufficient; or playing a portion
of one tape, and at a certain time shifting to the other tape may
be advisable. Individual situations dictate the best possible course
Sometimes it happens that a defendant on a tape recorded
conversation has made some remarks that are prejudicial against
him although there is probitive value in the comments.
Remarks such as racial slurs, comments about other crimes,
jail time, and other properly objectionable material should elicit
objections from defense counsel. Be prepared to offer a redacted
transcript and corresponding edited tape. Alternately the tape
signal can be interrupted while the edited comments pass without
being heard by the jury. In this case the Court may instruct the
jury that certain portions of the tape have no bearing on the case
and will therefore not be played for the jury.
Naturally all changes and redactions should be agreed
as soon as possible so as to eliminate the need for an audibility
hearing if possible, and also to give you a chance to prepare final
versions of the transcripts. Otherwise be prepared to bring
scissors and paste to trial.
Incidentally enormous responsibility rests in the hands
the person playing the tape since once a certain portion has been
ruled inadmissable and it is accidentally played for the jury, there
will certainly be a motion for a mistrial. Better to let a professional
handle this aspect of the presentation.
There is no question that during the course of under-cover
work certain off-color phrases are used, and are reflected in tapes
of these conversations. These should be left in the transcript to
give the jury a more accurate and true picture of what actually
happened at an undercover meeting. Expletives serve to
underscore the feeling that the jury is actually there listening to
the crime in which the participants are speaking as they usually
do, unaware of their presence.
During the Voir Dire of prospective jurors in a case
there are considerable off-color expressions on tapes, one might
ask the following:
"During the case there is a possibility that
tapes may be
played for you in which abusive or foul language occurs. Would
this offend you so much that it would interfere with your ability
to render a fairand impartial verdict in this case?"
While the undercover agent is on the stand you might
"And agent, why did you use the foul language which we heard
on the tape?" Even if due to an objection he cannot explain that
he wanted to be credible in his undercover role, the point will be
A final point about expletives; they are a reflection
defendant if he uttered them, and not of you, if you repeat them,
much like the old adage of not confusing bad news with the
messenger who delivers it.
Thus on summation, or during cross-examination of the
defendant if he should take the stand, don't be afraid to quote
exactly from the transcript. After all he said it, and he's got to live
There are a number of new techniques and products which
are currently being evaluated for introduction into the law-
enforcement market. Indeed there is an audio recording device
which uses no tape for storage of conversations. Instead the
material is digitized and stored in integrated circuit chips for later
downloading into a computer.
D-S-P, (or digital signal processing) is being introduced
a tool to be used in enhancement and optimization of audio as
well as video recordings. The results are far superior to the older
analog filters used in the past.
We have recently configured a digital enhancement
workstation with four different state-of-the-art D.S.P. enhancement
and analysis programs.
Devices are available to enable the investigator to decode
the outgoing touch-tones, as well as the incoming caller I.D. tone
burst, if present, during playback of wiretap tapes, for verification
of telephone numbers to whom and from whom calls are received.
We look forward to still more clarity and length of recordings
for use as a powerful investigative tool for law-enforcement.
1 . With cassettes, always be sure that the safety record
interlock tabs are knocked out of original and copy cassettes.
These are the plastic tabs which are on the edge of the
cassette opposite the side where the tape is exposed, and
are designed to prevent recorded material from accidentally
being erased or recorded over. When a cassette with tabs
removed is inserted into a standard cassette recorder the
machine physically cannot be put into a Record mode, thus
protecting the evidence.
2. With NAGRA tapes, the reels are very small and the
extremely thin. Steps should be taken to secure the end of
the tape, (preferably with a special NAGRA plastic reel
protector, but in a pinch with a rubber band) to prevent it from
unravelling. Also for NAGRA and cassette tapes, it is best
to keep the originals in sealed evidence envelopes, and mark
the envelopes so that the evidence-marking stickers do not
gum up the reel or cassette. All taped evidence should be
kept in envelopes and needless to say, not stored near any
magnetic fields, electric motors, speakers, heat, etc.
3. In the case of reel to reel recordings, either AID,
or bug types, it should be noted at what speed the tape is
recorded, so that the jury is not subjected to "Donald Duck"
sounds or other noise. The best solution is to have a system
whereby the machine operator can listen to the tapes in the
courtroom with everybody else disconnected, for cueing
purposes. This also helps when prejudicial remarks are to be
skipped or when selected portions are to be located during
summatiori or deliberation.
4. Please note that index counters on cassette recorders
reel-to-reel machines are not feet, but arbitrary units, and also
that generally there is no index counter correspondence
between different types of machines. Thus, when indexing
a tape, it should be noted on which machine the indexing was
5. Also please note that if a spot 3/9 into the tape is
a tape which is played to that point, it is possible (and in fact
probable) that if the tape is fast-forwarded to that same point,
at a later time the index will be slightly different. This is due
to the tightness and looseness of the wrap of the tape in
6. If a tape should break accidentally, it can be repaired
someone proficient in tape editing. Recording studios and
radio stations do it every day. The proceduie is to simply
document everything and let the expert perform the surgery.
Incidentally, there are even available cassette splicing kits
for the very thin tape used in cassettes and Nagra recorders.
7. A clean machine is a happy machine. The capstan roller
wheel that moves the tape) and the heads of all tape recorders
become dirty from normal use. If not cleaned periodically,
there is a danger of a tape being stuck and unwound, and
severely damaged in the process. All it takes are some Q-
tips and some denatured alcohol, hardware store variety, not
8. We have found that a good blank cassette to use for
copies is the TDK DC-30 (60 & 90) for 30, 60 and 90 minutes
total, respectively. The physical cassette case is strong and
9. In making copies, always connect the playback machine
the record machine electrically. Do not make copies with the
microphone of the record machine, attempting to pick up the
sound from the speaker of the playback unit. Such a copy
is virtually worthless. Call us anytime for assistance in
connection with making enhanced copies, transcripts or any
other problems associated with taped evidentiary material.
Paul Ginsberg, President
PROFESSIONAL AUDIO LABORATORIES
Dear Mr. or Ms. Attorney,
We have presented an overview of the basics involved in
the use of
audio taped evidentiary material from a prosecution point of view.
We hope that this guide provides you with some useful
information and we look forward to assisting with your next tape
case should the need arise. Please call if we can be of assistance in
connection with transcript preparation, production of copies,
presentation of evidentiary material in the dearest possible manner
using specially fabricated state-of-the-art filtering and processing
equipment. We can advise you at no cost or obligation as to the
best course of action in connection with taped evidentiary material.
PROFESSIONAL AUDIO LABORATORIES, INC. with Is years
experience has assisted the U.S. Department of Justice through 23
offices coast to coast with Federal court qualified expertise in 23
Federal Districts, in over 1,000 cases.
Paul Ginsberg, President
PROFESSIONAL AUDIO LABORATORIES, INC.
P.S. Additional copies of this guide are available from us as
required. Call with requirements.
A Prosecutor’s Guide to The Use Of Audio Taped Evidentiary Material.
Copyright © 1992 by Paul
Ginsberg. All rights reserved. No part of this book may be reproduced
in any form or by any means
without written permission from the author.