LOS ANGELES - A man arrested at Los Angeles International Airport wearing a bulletproof vest and flame-resistant pants is not cooperating with federal officials working to discover why he was headed to Boston with a suitcase full of weapons, authorities say.

Yongda Huang Harris, 28, was taken into custody during a stopover on a trip from Japan when U.S. Customs and Border Protection officers reported noticing he was wearing the protective gear under his trench coat, triggering a Homeland Security investigation.

A search of Harris' checked luggage uncovered numerous suspicious items, including a smoke grenade, knives, body bags, a hatchet, a collapsible baton, a biohazard suit, a gas mask, billy clubs, handcuffs, leg irons and a device to repel dogs, authorities said.

Harris has not cooperated with authorities attempting to interview him, according to a U.S. official who spoke on condition of anonymity.

The official said Harris, who was taken into custody on Friday, is not believed to be linked to a terrorist organization. His motive, however, has not been determined, the official said.

Harris has been charged with one count of transporting hazardous materials, an offense that carries a maximum penalty of five years in prison. He made a brief court appearance on Tuesday, but his arraignment was delayed until Friday, and he was ordered held until then.

Harris is a U.S. citizen whose permanent residence is in Boston, though he recently started living and working in Japan, officials said. Attempts to reach Harris' family in Boston and his associates were unsuccessful.

His attorney, Steven Seiden, was unavailable to comment, said Chris Williams, a spokesman for Seiden, who also represents Mark Basseley Youssef, the man behind the anti-Islam video that recently sparked violence in the Middle East.