NAHA, Okinawa — Police investigating an August explosion that killed a Japan Air Self-Defense sergeant say they’ve traced the weapon to the U.S. military.

Senior Master Sgt. Takio Tamura, 53, a military surplus items collector and dealer, was cleaning Vietnam-era rocket-propelled grenades at a friend’s Okinawa City junkyard when one exploded, killing him.

An investigation revealed he had been collecting and dealing in surplus weapons, clothing and other military items for more than 20 years.

Police looking into the origin of the rocket-propelled grenades this week said they received a report from “a U.S. military agency” that similar munitions were used in April for training at Camp Hansen.

Authorities would not identify the source of the report.

A Marine Corps spokesman said he is not aware of any such report originating with the U.S. Marine Corps, which runs Camp Hansen.

A police spokesman said the report they received last week was the first indication the shells, manufactured in 1973, were still used in training.

Investigators are looking into whether someone could have sneaked onto the training area to obtain unused shells, he said.

Police are now investigating other possible violations of Japan’s strict Firearms and Swords Control Law.

After Tamura’s death, searches of his two homes showed they were used as warehouses for his hobby. Both neighborhoods were evacuated Sept. 6 while U.S. Air Force explosive ordnance experts destroyed live rocket-propelled grenades.

Police also raided military surplus businesses in central Okinawa and the homes of several flea market stall operators who stocked military surplus items.

As a result, an illegal flea market that operated along a public access road in the Kadena Ammunition Storage Area in Okinawa City was ordered closed. The investigation showed that Tamura resold some of the surplus items he collected at a stall there operated by a friend.

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