Summing up
Although circumstantial it is quite clear once you add the all the little stuff as well. Like the P61 pilots log book being taken and not the records but the missing records of his squadron for that 2 day period. And that those 2 days are the only missing records.
The fact that the P61s were no longer escorting due to the lack of opposition but were casting further afield. They were in fact operating within Sempai 61’s operational area. Both well documented facts.
We do know that 3 Liberators were shot at, one went down in flames as reported by the P61 crew, they also reported another damaged and that they made a total of 6 passes. I would surmise that they actually damaged two aircraft and not the one as was claimed.
Officially the two damaged aircraft were losed, reason unknown, there is some speculation about weather, but all the reports from the other aircraft was that the weather was good. But bad over target DZ. Both crash sites are quite close. About 20 miles apart. The first is on a reverse slope the second is on a slope at right angle to the line of flight.
There are two points. The weather was bad over the DZ, this could have played a role in the lack of the P61s ability to ID what would have been very familiar lines of a Liberator to an American pilot. The second is that it would appear that the aircraft did not just fly into a granite cloud and that some pilot input was needed or that the pilot was unable to control the aircraft. Give that this is the same ground flown over on the way out. Leaves me to guess that both aircraft tried to reverse course because they could not gain altitude, why? Because of damage? Or mechanical problems?
Politics
The Poms. And Mountbatten. Well they did their best to arm every resistance fighter who would kill a jap they could, Communists in Malay, independence fighters in Sumatra and the French resistance in Indochina. America was big of forcing or had the view that France England and the Dutch should not get there old colonies back after the war. To that end they had policies while under Stillwell or Vinegar Joe to just hinder or prolong the war if it suited there end. Refusing to provide American shipping to get British troops from BBK to Sumatra for example or refusing or even getting Chinese patrols to hunt French resistance fighters in Indochina or at least disarming them. In the meantime the Americans were training the Vet Mhin in china?. So based on this facts it looks highly likely that there was a conspiracy to hinder or that the Americans found it acceptable to shoot down RAF aircraft . but not so. We also know that SOE was not informing the Americans what they were doing. So how did the p61 know they were there? Also given that there were a number of aircraft operating that night. Why was only the 3 aircraft attacked on the same track? Why were there not more P61 flying and attacking the other aircraft at their targets?
Back to politics. October 1944 Stillwell got the boot, he was a bumbling fool anyway. His replacement was much smarter and was well known to have seen the communist threat as much more of a problem than as the possible recolonization. This panned out when Truman took over. From a really ani colonization policy to a policy of do nothing.
It is in my opinion that these 3 aircraft were losed because of 1, Lack of training of the Yanks, 2 lack of experience of the Yanks 3, The Americans Not informing SEATC of a change in SOP 4, the breakdown in communications in SEATC firstly between Stillwell and Mountbatten, secondly Stillwell’s American first policy over a win the bloody war policy. Which lead to the operations guys on both teams not talking to each other?