(CNN) -- Authorities evacuated a Bermuda-bound flight at Philadelphia International Airport in Pennsylvania Thursday after one of three people loading the plane didn't appear to belong and suddenly left the area, police said.
It appeared that the man in question was properly credentialed to be in a secure area, but was working on a plane that he wasn't supposed to, FBI spokesman J.J. Klaver said. When he was questioned by the other baggage handlers, the person left in a baggage loading cart, he said.
US Airways Flight 1070 -- which police said was bound for Bermuda with 102 passengers and five crew members -- was towed to a secure part of the airport, where baggage was removed from the plane to be screened by bomb-sniffing dogs.
The plane tested negative for explosives, and the incident is not believed to be terror-related, said Klaver. The investigation was ongoing, he added.
In addition, no narcotics were found on board the plane, said Stephen Sapp of Customs and Border Protection.
"There's nothing explosive, nothing hazardous," Klaver said.
He also said that there was no apparent failure in airport security processes.
Federal and local police at the airport had been searching for a man in uniform who was not wearing identification on the tarmac, a law enforcement official told CNN.
"This could be a suspicious person or it could be nothing," the official said.
The rest of the airport was fully operational and not affected by the incident, said spokeswoman Victoria Lupica.
The passengers remained in the terminal, said Todd Lehmacher, spokesman for US Airways. The airline hoped to get them back on the plane and headed for Bermuda once authorities allow it, he said. CNN's Carol Cratty and Jeanne Meserve contributed to this report.