There was no evidence that JB had tampered with, cleaned or destroyed any audio tape connected with or associated to the answer phone machine that EP seized from his cottage - if such evidence existed the prosecution would surely have relied upon it at the time of the trial...
But they did not...
EP seized this answer machine, as part of their investigation, at a time when they almost certainly had gathered sufficient intelligence to believe that the answer phone machine might hold some vital clue or other to help the police establish what had actually taken place...
I am convinced that EP obtaioned the itemized billing for the phone account at whf, and they they discovered that there was two calls made from the scene during the early hours of 7th August 1985...
(1) - a call made to Jeremy's cottage at 3:15am
(2) - a call made to the police at 3:16am
What is more, I believe that EP knew how long each call had lasted - with this information in their possession, I believe they seized the answer phone machine from Jeremy's cottage, and checked to see if there was any evidence on the audio tapes that matched the duration of the call that was made from whf at 3:15am. If they had found any evidence of this, they would almost certainly have used it at the trial to suggest to the jury that Bamber had been at the scene and that he had called his cottage from whf, but evidence was recorded on his answer machine, etc...
The fact that they found no such evidence, led the police to conclude that Bamber must have hired a hit man, who called him from the scene, once the murders had been finalized - but inquiries in this direction, also proved fruitless...
I think there are very strong grounds for believing that there were or may have been two calls made from whf that morning, one timed at 3:15am, made to Jeremy's cottage, and the other, timed at 3:16am, made to the police...
The clock in the control room was ten minutes fast, and this can be relied upon to show that the first message recorded at the police station, related to a call from Ralph Bamber, timed at 3:26am, but the real time was 3:16am...
The next call, made by Jeremy to the police was timed as, 3:36am, but because the clock in the control room was ten minutes fast, the real time was 3:26am...
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There is other information available to back this up:-
None more significant, than a reference in a Police Major Incident Project document, which states that at 03:45am, PC Lowe had seen an unidentified male suspect at WHF?
How could PC Myall have seen this unidentified male suspect at 3:45am, if the police car he arrived at to the scene, did not officially arrive, there until 3:48am? This problem is solved by reference to the fact that the clock in the control room was ten minutes fast, so although the record contained in / on message 3:26am, states that patrol car, CA07 was dispatched to the scene at 3:35am, and it arrived there at 3:48am, the actual time it was deployed to the scene was at 3:25am, arriving at the scene at 3:38am - allowing PC Myall to make the sighting of the unidentified male at the scene (inside the bedroom window of the farmhouse when he was in the grounds along with PS Bews, and JB)...
JB officially arrived at the scene, at 3:52am, but because the clock in the control room was ten minutes fast, the actual time JB arrived at the scene was at 3:42am...
Another area of contention relating to the timing of the telephone calls, involves the call JB made to JM, which was originally said to have taken place at about 3:30am, but which was later displaced to the earlier occasion of about 3:15am...
I think the timings were all altered because of the clock in the control room being ten minutes fast, and later evidence to show that the clock in the bedsit where JM was living being about 15 minutes fast...
Once you know all these factors, including for the possibility that EP obtained billing details for the phone at whf, and that there was / is evidence that two calls were made from whf, one timed at 3:15am, made to JB's cottage, and the second one, at 3:16am, to the police, the rest just falls into place, including the reason why EP seized JB's answer phone...
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By the time of the trial, (October 1986) EP were relying upon the fact that the clock in the control room, was ten minutes fast, and the two different phone message logs, (3:26am and 3:36am) were relied upon to try and suggest that the content referred to the same call, but they were not - a fact provable once the billing details were disclosed showing that there had been two calls made from whf, one at 3:15am, and the other at 3:16am...
Details of the first call timed at 3:26am, were photocopied onto the reverse of another original log which had been compiled from information received from the scene timed at 4:02am...
This was a crucial forgery designed to join both calls together, (3:26am and 3:36am) as being one and the same - exposed, because of the fact that the original details as per the 3:26am, phone call from Ralph Bamber, were not disclosed, and to this day, despite some 25 years having elapsed, the original version of these notes is missing, has been destroyed or EP and th DPP / CPS, refuse to disclose it, under pii...