Serial 2341

FBI LABORATORY
FEDERAL BUREAU OF INVESTIGATION
WASHINGTON, D.C. 20535

October 31, 1979

To: SAC, San Francisco (89-250) (Sqd. 1)
From: Director, FBI
Re: RYMUR (00: San Francisco)

Examination requested by: SAC, San Francisco
Reference: Airtels dated May 4, 1979 and July 3, 1979
Examination requested: Voice Comparison –Enhancement – Duplication
FBI file no: 89-4286
Lab. No.: 90507058 E SH/90710030 E QZ

Remarks:

No transcriptions were prepared of the pertinent conversations on specimens Q1289 and Q1290 by the Technical Services Division, as investigative personnel being more familiar with names, dates, voices, and other matters pertinent to the investigation are ordinarily better able to resolve questionable portions of the recording.

Copies of Q1289, Q1290 and Also submitted items have been submitted to the Technical Evaluation Unit of the FBI Laboratory for such examination as they deem appropriate.

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FBI LABORATORY
FEDERAL BUREAU OF INVESTIGATION
WASHINGTON, D.C. 20535

October 31, 1979

To: SAC, San Francisco (89-250) (Sqd. 1)
Re: RYMUR (00: San Francisco)
FBI file no: 89-4286
Lab. No.: 90507058 E SH/90710030 E QZ

Specimens received: May 4, 1979

Also submitted: Two copies of five Xerox pages of notes.

Specimens received: July 9, 1979

Q 1289 – One Scotch C-60 magnetic tape cassette marked in part “Tape 2” on side 1.
Q 1290 – One Mazell C90 magnetic tape cassette marked in part “Tape 3” on side A.

Results of examination:

The unknown voices on the radio transmissions on specimens Q1289 and Q1290 were subjected to spectrographic (voiceprint) examination, which revealed that the quality was too poor to allow meaningful comparisons with known voice samples.

Once identification by the spectrographic method is not considered a positive means of speaker identification and the result of such examinations are furnished for investigative guidance only.

Three electronically processed copies each were prepared outside 1 of specimen Q1289 and side A specimen Q1290 to enhance the radio transmissions, with one copy on a magnetic tape cassette and two copies on 5-inch reels of magnetic tape in a full-track configuration and recording speed of 3 3/4 inches

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per second. Only a slight improvement in voice intelligibility could be obtained in the processed copies due to the high level distortion in the speech frequency range.

Specimens Q1289 and Q1290, and two processed copies will be forwarded to your office under separate cover via registered mail.

One 5-inch reel processed copy each of Q1289 and Q1290 was personally delivered to the Technical Evaluation Unit of the FBI Laboratory on 10/2/79.

[Page 4 through page 7 are handwritten notes of FBI laboratory]

[Page 8 through page 9 is duplicate copy of Serial 2177, the text of which may be found here.]

Originally posted on November 10th, 2020.

Last modified on November 19th, 2020.
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