Strong Japanese naval force in Indian waters active according to the U.S. Joint Intelligence Committee. Daily summary dated 15 April 1942.

An item reported that on 6 April the Indian sloop Indus after she was bombed sunk of the coast of Burma. Since 3 April destroyed the Japanese at least 16 Allied merchant ships in the Indian waters. The Japanese aircraft carriers until recently active in the Bay of Bengal seemed to have gone to the eastward probably to replace their heavy aircraft losses. Despite contradictory and confusing information it was not believed that to date more as 3 battleships, 4 aircraft carriers, 5 heavy cruisers, 1 light cruiser, 1 destroyer squadron and 12 submarines executed offensive missions in the Bay of Bengal.

Source

Map Room Papers (Roosevelt Administration), 1942 - 1945. U.S. Joint Intelligence Committee. Daily summary No. 126 dated 15 April 1942.