The discovery of a stowaway who died in the wheel well of a British Airways jet has raised questions about how the young man slipped through airport security and got onto the plane.

Investigators were trying to determine where the boy, who was carrying identification and letters suggesting he was a 17-year-old South African, gained access to the jetliner, officials said Monday. The victim's name was not released.

The pilot found the body Sunday afternoon in the front wheel well of the 747-400 during a routine inspection at Los Angeles International Airport shortly before the plane was to return to London. The well compartment is enclosed but not pressurized or heated.

Authorities were working with the South African Consulate to check the authenticity of documents found on the youth and to locate possible family members. An autopsy was scheduled Tuesday, said county coroner Capt. Ed Winter.

The death raises concerns about possible holes in air security, experts said.

"The question is how did he get there? If he could be there himself, why not [with] a 150-pound [67.5-kilogram] bomb?" asked Brian Jenkins, a terrorism and homeland security expert at Rand Corp., noting that Heathrow's security is extremely tight.

Jenkins also questioned why, if the teen had gotten aboard a few days ago, security inspections had not found him sooner.

The FBI was trying to determine where the youth boarded. British Airways Flight 283 had arrived from London Heathrow Airport on Sunday. Before that, it had made trips to Hong Kong; Singapore; Cape Town, South Africa; and Vancouver, said Alan Proud, a spokesman for the airline. The flight was last in Cape Town on Jan. 22, Proud said.

On Jan. 12, the body of a young African man was discovered in the wheel well of a Delta plane that landed in Atlanta from Dakar, Senegal. Authorities determined the man hid in the plane in Senegal and was suffocated by the landing gear.

In 2000, a man lived through a freezing Air France Boeing 747 flight from Papeete, French Polynesia, to Los Angeles.