USS army aircraft attacked patrolling Japanese flying boats in the Alaska areaaccording to the U.S. Joint Intelligence Committee. Daily summary dated 6 August 1942

An item reported that on 4 August USS army aircraft attacked two patrolling Japanese 4-engine flying boats in the Alaska area. One was set on fire and crashed around 10 miles southwest of Adak Island, the other disappearing uncontrolled in the clouds and seemed to have crashed around 15 miles southeast of Adak Island.

Source

Map Room Papers (Roosevelt Administration), 1942 - 1945. U.S. Joint Intelligence Committee. Daily summary No.239 dated 6 August 1942.