"The one thing that concerns me is he was able to board a plane internationally with all these weapons and whatnot, and nobody in Japan, nobody in Korea, bothered to find these things until he got to America," said Gadisa Goso, 29, a school administrator and neighbor of Harris' mother in Boston. "That's a big concern for, like, for the U.S."
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 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 were unsuccessful. His attorney, Steven Seiden, was unavailable, said spokesman Chris Williams, who described Harris as very intelligent, earning A's in high school and college calculus.
Harris traveled from Kansai, in western Japan, to Incheon, South Korea, before landing in Los Angeles.
Security at Japanese airports is similar to the U.S. They use metal detectors and X-ray screening on every person and every bag, both checked and carry-on. Airport and immigration officials at Kansai International Airport said Wednesday that airlines are primarily responsible for luggage inspection, but no problematic cases have been reported recently.
An immigration officer at Kansai, Masahiro Nakamoto, said authorities did not report anything suspicious at the time Harris boarded, but arriving passengers are checked more closely than those leaving the country. Spokesman Keisuke Hamatani said Kansai security officials had not reported any suitcases containing the hazardous materials U.S. authorities say they found in Harris' luggage.
Yasunori Oshima, an official at Japan's Land and Transport Ministry's aviation safety department, said there had been no official inquiry or request from U.S. authorities to look into the case, which he said would have been more of a concern if the hazardous materials were brought on board rather than checked.
"The case does not seem to pose any immediate concerns about aviation security measures in Japan," he said.
Airport police said they do not believe the case constitutes illegal conduct under the Japanese domestic criminal code, but Japan may cooperate at the request of U.S. investigators.
Sullivan reported from Washington. Contributing to this report were Associated Press writers Shaya Tayefe Mohajer in Los Angeles, Rodrique Ngowi in Boston, Eric Talmadge and Mari Yamaguchi in Tokyo, and Alicia A. Caldwell in Washington.