A United Airlines flight bound for Los Angeles International Airport had to return to its origin of Honolulu after a “potential security concern” was found in a lavatory onboard, according to an airline spokesperson.  

UA1169 left Daniel K. Inouye International Airport airport code HNL at 9:40 p.m. Tuesday, according to flight tracking data from FlightAware. Radar data shows that, about an hour and a half after taking off, the flight made a sharp 180 degree turn and began going back towards HNL. 

This was due to a “potential security concern” found written on a lavatory mirror, a United Airlines spokesperson confirmed to affiliate KTLA. What the alleged threat said was not disclosed.

Upon landing safely back in Honolulu, law enforcement searched the plane; the spokesperson did not elaborate on whether anything was found.  

“We are rebooking customers on another flight to Los Angeles that departs later this evening,” the spokesperson told KTLA on Wednesday morning.  

The Boeing 777 was carrying 339 passengers and 10 crew members. 

Tuesday evening’s discovery of the “potential security threat” came on the same day a passenger on a Hawaiian Airlines flight leaving San Diego for Honolulu was arrested for an alleged bomb threat.

A Port of San Diego Harbor Police Department spokesperson confirmed to KTLA sister station KSWB/KUSI that a flight attendant on that flight reported to the captain that a passenger reported a possible bomb onboard; the captain then called police.

However, following a search of the aircraft, authorities found “nothing suspicious,” and passengers were able to leave San Diego about six hours after their initial scheduled departure time.