High Quality Content by WIKIPEDIA articles! The "Double Tenth Incident" or "Double Tenth Massacre" occurred on 10 October 1943, during the Second World War Japanese occupation of Singapore. The Kempeitai – Japanese Military Police – arrested and tortured fifty-seven civilians and civilian internees on suspicion of their involvement in a raid on Singapore Harbour that had been carried out by Anglo–Australian commandos from Operation Jaywick. Six Japanese ships were sunk, but none of those arrested and tortured had participated in the raid, nor had any knowledge of it. Fifteen of them died in Singapore`s Changi Prison.