Using commercially available audio analyzers, I closely studied the magnetic marks in an effort to identify a “signature” for begin erasure events. From this scrutiny and the images of the magnetic marks scattered throughout the Advisory Panel Report, I discovered what I believed to be a signature marking the start of each erasure. I compared the signature images at the ten begin-erasure points on the tape with the magnetic mark 275 seconds into the tape gap identified as “transient noise.” I also contrasted the images of the five “end erasure” events from the gap. As shown in Figure 3, the similarity of the magnetic mark at 275 seconds to the other begin-erasure events, especially those at 0 and 49 seconds, convinced me that the mark identified as transient noise was actually a begin-erasure event.

Based on these findings, I restructured the sequence of tape events into ten erasures, dividing what was previously the third erasure (beginning at 155 seconds and ending at 611 seconds) into two separate erasures (the first from 155 to 275 seconds, and the second from 275 to 611 seconds).

The initial set of loud buzz erasures lasting 4 minutes, 35 seconds was now consistent with Woods’ admission to erasing between 4½ and 5 minutes of the tape.With this seemingly minor adjustment, I could now explain, at least theoretically, the structure of the clicks, pops, and buzzes that occur during the 18½-minute gap.

On October 1, 1973, Rose Mary Woods was reviewing the tape containing President Nixon’s June 20, 1972, 11:26 A.M. meeting with chief of staff Bob Haldeman when she made a 4½ to 5- minute erasure. Woods claimed the erasure was an accident.

Analysis of Initial 4 Minute, 35 Second Loud-buzz Erasure:
Unbeknownst to anyone at the time,Woods’ tape recorder was faulty, inadvertently storing the AC hum from the connected power line onto the tapes it erased. In addition, the AC hum on the power line in Woods’ office was louder than normal, therefore, erasures made in Woods’ office using the faulty tape recorder caused a loud buzz to be stored on the tape. Consistent with Woods’ admission to erasing about 4½ to 5 minutes of the tape in her office using the faulty tape recorder, the 4 minute, 35 second segment exhibits this characteristic loud buzz. However, Woods’ tape recorder required manual intervention to both start and stop erasing. Woods claimed the erasure was an accident, but an examination of the tape shows that this segment is composed of three separate erasures, indicating Woods’ erasure was deliberate.

Following Woods’ 4 minute, 35 second erasure on the tape is a 12 minute, 46 second soft-buzz erasure. On November 6, 1973,Woods told Robert Bennett, the White House tapes custodian, that she found a gap where she expected a recorded conversation. I suspected that this was the day that she found the unexpected erasure segment. I assumed Woods was alerted to check the tapes that day as a result of Deep Throat’s “deliberate erasures” tip. Just the day before,Carl Bernstein, Woodward’s reporting partner, had begun asking White House press secretary Ron Ziegler and others at the White House questions about possible erasures as a result of Deep Throat’s tip to Woodward.

Analysis of 12 Minute, 46 Second Soft-buzz Erasure:
This soft-buzz segment of tape consists of four separate erasures. Therefore, this erasure segment was also deliberate. While the AC hum on the tape during this erasure segment is consistent with Woods’ faulty tape recorder, the lower level of AC hum stored on the tape (soft buzz) during this erasure is inconsistent with the louder AC hum found on the power line in Woods’ office. Thus, sometime after Woods’ initial 4½-to-5minute erasure, an unidentified person deliberately erased 12minutes, 46 seconds of the tape using Woods’ faulty tape recorder. However, this erasure appears to have been made somewhere other than in Woods’ office.