More Japanese Letters Seized; Navy Tightens Coast Patrol

SAN FRANCISCO, Saturday, Dec. 25. -- (UP) -- The Navy tightened its patrol of California waters tonight and customs officials made new seizures of consignee mail aboard Japanese liners, giving impetus to rumors that the federal government actively is investigating a possible widespread espionage plot.

Packets of approximately four hundred letters were reported seized by customs officials aboard the Hokkai Maru, the Kinai Maru and a third Japanese vessel at Los Angeles.

The consignee mail had not gone thorough regular postal channels, but was included with company papers in packages handled only by company agents.

Postal authorities here held several letters taken from the Tatsuta Maru. Reports that the letters were suspected of containing espionage information concerning activities at the Bremerton Navy Yard were not confirmed.

Alien Craft Sought

At San Diego, the Navy sent two of its speedy pocket cruisers, the U.S.S. Clark and McDougal, to reinforce ships patrolling Coronado Channel in search of unlicensed craft of alien origin.

Customs officials refused to discuss mail seizures. They said the seizures "presumably" were made because consignments aboard the Japanese ships were in violation of postal laws.

It was reported unofficially that the Mexican government is co-operating with the United States Navy in checking and inspecting "alien craft."

Several fishing boats have been stopped and examined, including the Nancy Hanks, said to be owned by an American-born Japanese.

San Diego rumors indicated that Mexico had sent some of its new thirty-knot patrol boats to the West Coast of Mexico and Baja California. These patrol boats usually carry several large-calibre machine guns.

It also was reported one of Mexico's new super-gunboats, armed with three-inch combination anti-aircraft and naval rifles, also had been assigned to the patrol to check activities of tuna fishing fleets plying off Southern California and Mexican shores.

One report said alien hydrographic experts had been discovered making soundings and charts of Southern California waters.

Greatest Since War

The Customs Service said the "channel patrol" at San Diego was part of the greatest drive since World War days against illegal registration of American boats. It is against the law for a foreign owner to place his boat in American registry through a dummy. The Nancy Hanks was suspected of carrying such a registration. A large percentage of the fishing boats operating from California are Japanese-owned.

At Mare Island Navy Yard, 450 miles north of San Diego, where virtually no fishing fleets operate, guards were particularly vigilant.

A report that a bomb had been found aboard the cruiser Indianapolis, anchored at Mare Island, was denied by Rear Admiral Clarence Kempff. The time-bomb, according to the report, was found just before it was scheduled to explode.