2 âunknownsâ killed in attack on Pearl Harbor identified as Indiana brothers On Dec. 7, 1941, the Trapp brothers were assigned to the battleship USS Oklahoma, which was moored at Ford Island, Pearl Harbor, when the ship was attacked by Japanese aircraft. (Source: The Defense POW/MIA Accounting Agency) By HNN Staff | May 10, 2021 at 4:40 PM HST - Updated May 10 at 4:40 PM HONOLULU, Hawaii (HawaiiNewsNow) - The remains of two brothers who were onboard the USS Oklahoma when the Japanese military attacked Pearl Harbor have been accounted for. The Defense POW/MIA Accounting Agency made the announcement Monday. Navy Fire Controlman 2nd Class Harold F. Trapp, 24, and Navy Electricianâs Mate 3rd Class William H. Trapp, 23, were both on the Oklahoma when it was hit by multiple torpedoes, causing it to sink.