(AP) - A jetliner bound for Madrid was returned to Kennedy International Airport as a precaution Thursday evening after a passenger reported strange wiring in the bathroom, but no explosive device was found, law enforcement officials said.

Delta Flight 126 left the gate at about 8 p.m. and returned around 10 p.m. after the report. A U.S. Marshal was onboard the plane, and the New York Police Department bomb squad and FBI met the flight as a swarm of law enforcement vehicles crowded the plane and the passengers were evacuated.

The wires were determined to be non-explosive but apparently didn't belong to the plane, said Paul Browne, chief spokesman for the NYPD. Investigators briefly questioned two passengers, a woman who reported having difficulty breathing at the time the wires were discovered, and a man who apparently had been the last to use the bathroom. Officials were concerned the woman may have been creating some sort of diversion, but that was determined not to be the case. The male passenger denied having anything to do with the wires. Both passengers were released.

It's not clear how many people were on board. Calls to Delta and the Transportation Security Administration were not immediately returned.

In May, a US Airways jet traveling from Paris to North Carolina was diverted to Maine after a French passenger handed a note to a flight attendant mentioning that she had a surgically implanted device, raising fears of a terror scenario that security officials had warned about. After landing, the plane taxied to a remote part of the airport where law enforcement officials removed the passenger.