Enemy submarines active off Californian Pacific coastline according to the U.S. Joint Intelligence Committee. Daily summary dated 21 December 1941

An item referred to the DIO 12th Naval District reporting that it was certain that enemy submarines were active off Blunts Reef and Santa Cruz, Pacific Ocean coastline, California, USA.

Source

Map Room Papers (Roosevelt Administration), 1942 - 1945. U.S. Joint Intelligence Committee. Daily summary No. 11 dated 21 December 1941.