LOS ANGELES (AP) — A teacher arrested at Los Angeles International Airport wearing a bulletproof vest and with checked bags containing knives, body bags, a smoke grenade and other weapons also had files on his computer detailing how to kidnap and kill people, federal authorities disclosed Friday.

In addition, Yongda Huang Harris had files revealing he has a "strong interest" in sexual violence against girls, including a video titled "Schoolgirls in Cement," Assistant U.S. Attorney Melissa Mills said.

One publication was entitled "Man Trapping" and showed how to hunt and trap humans, she said.

The prosecutor detailed the discoveries during a court appearance by Harris, 28, a Boston University graduate who had been working in Japan as a junior high school teacher.

The bespectacled Harris was shackled in handcuffs and wore a white prison-issued jumpsuit, along with a blue surgical mask over his mouth due to a throat infection.

Before the detention hearing, he crossed and rubbed his arms, appearing to be cold. He often turned and spoke with his attorney Steven Seiden.

U.S. Magistrate Judge Paul Abrams declared Harris to be a flight risk and ordered him held without bond until he stands trial.

Harris is charged with one count of transporting hazardous materials, for the grenade, and could face up to five years in prison if convicted. He did not enter a plea.

Seiden said the weapons Harris was carrying were meant for protection and necessary because Harris was once attacked on the streets of Boston.

Seiden described Harris as scared and timid. Harris carried some of the items to defend himself, Seiden said.

"He may have interests that are not of the norm, but that doesn't mean he's carrying out any type of harm to anyone," Seiden said.

Seiden also said Harris didn't have any previous psychological issues.

Harris was arrested on Oct. 5 wearing the bulletproof vest under a trench coat along with fire-resistant pants and kneepads. His attire attracted the attention of law enforcement, and when his luggage was checked the weapons cache was found, authorities said.

On the computer was a document with schedules for schools in Japan showing when students arrived and left.

Harris was arrested during a stopover in Los Angeles on his trip from Japan to Boston.

The search of his checked luggage uncovered numerous suspicious items, including a hatchet, knives, collapsible baton, biohazard suit, billy clubs, handcuffs, leg irons and a device to repel dogs, authorities said.

The items "looked like a kidnap kit," prosecutor Mills said.

Seiden, who also represents the man believed to be behind an anti-Muslim film that roiled the Middle East, said the clothing worn by Harris when he was arrested is common in Asian countries and described the outfit as resembling martial arts attire.

He disputed the government's contention that body bags were found inside his client's luggage. Harris had a large duffel bag for moving items, the lawyer said.

Harris is a U.S. citizen whose permanent residence is in Boston and was traveling there because his stepfather recently died, Seiden said.

His flight originated in Japan and he got off in South Korea, where security officials screened Harris and his carry-on luggage. The smoke grenade made it onto the plane in his checked luggage.

The grenade was X-rayed in Los Angeles and police determined the device fell into a category that is prohibited on passenger aircraft. The knives and items are permissible in checked bags, while the vest and pants are not listed among items prohibited in aircraft cabins.