Another element is that the identification of the vessel as a DD might have come from Commander Moerman in Makassar when interviewing Meijer. Meijer was a young engineer who experienced a dreadful thing in a highly stressful circumstance. CdR Moerman (not the captain of Aug.) would have gone through lengths by questioning Meijer about the ship: how did it look like, how many guns, etc. Meijer may have said: quite big with big guns with shields for and aft, two funnels, one of the rear guns facing forwards, etc. Sounds like a DD or what? But check out the pics of the earlier series of IJN minesweepers
Minesweepers and Massacres
Still not concluding it WAS a minesweeper
but I could refer to two other massacres that evolved around IJN minesweepers, just to open people's minds:
1 the Laha (Ambon) massacre in which the crew of a sunken minesweeper took part (in revenge of their sunken ship and lost comrades) and
2 the Tarakan massacre which followed an alleged KNIL MASSACRE of the crews of two sunken minesweepers. This happened when the coastal artllery battery at Karoengan had ignored surrendering (read the Dutch official historian De Jong about this, not the KNIL historians like Nortier - KNIL troops allegedly machinegunned IJN survivors in the water!).
Good points about the use of SMGs but they could have been the real Tommyguns, weapons captured from previously captured KNIL units on Borneo, Celebes or Ambon...
The reason of these massacres are indeed beyond our (western) thinking, but I suppose they may have been a normal part of oriental warrior codes of honour. Imagine the IJN ship commander receiving orders to find that tanker spotted by the planes and bring it in for later use by the IJN. A fine and highly useful prize in a war were every drop of oil counts! But he failed didnt he? And the culprits for his failing were at his mercy. In the face of his crew captain Moerman had outsmarted him by stopping the engines and thus by seemingly cooperating, but in the same time opening the valves. IJN CO loses face, now he must avenge.