I decided to call up a vet I know and asked him about your question.
Again, he doesn't recall seeing fuel used on prisoners. He said The Imperial Japanese troops usually use fire to raze entire towns in retaliation for guerilla activity.

I asked this question with my Dad and he essentially said the same thing. Bayonet, sword, shootings were the norm.

Of course, I understand that different conditions could exist in different POW camps. It's possible that fuel was indeed used in that particular POW camp and not in the other POW camps in the Philippines.