A telephoned bomb threat that forced a Southwest Airlines flight to divert to Phoenix Sky Harbor International Airport on Monday drew a massive police response and an investigation that delayed flights, disrupted traffic and held the Austin-bound passengers in Phoenix for most of the evening.
No explosive device was found in an extensive search of the plane, an FBI spokesman said late Monday.
The FBI and Phoenix police bomb squad and K9 units descended on the scene and scoured every inch of the plane, examined each piece of luggage and interviewed the 143 passengers on board the flight, which originated in Los Angeles.
"The FBI and law-enforcement partners are responding to conduct an investigation of the aircraft, as well as to determine the person (or people) responsible for the threat," FBI spokeswoman Laura Eimiller said Monday afternoon.
Flight 2675, which departed from Los Angeles at 2:12p.m., landed safely in Phoenix at 3:57p.m. The "cautious" investigation remained in full swing more than five hours after it began.
A plane was available to take the travelers to Austin, but the screening process continued into the night.
The plane had landed at Terminal 4 but was hauled to an isolated area on the western side of the airport, away from other terminals, according to a statement from the airport.
Phoenix police Sgt. Steve Martos said the careful search of the plane and the passenger interviews are common operating procedure when a threat of this nature comes in.
"We want to use an abundance of caution," Martos said.
It is possible that "the people on the plane may know" something about the threat, Martos said about the need to interview the passengers.
Two F-16s monitored the flight as it landed at Sky Harbor, according to a NORAD spokesman.
The two F-16s that monitored the flight had been launched from Davis-Monthan Air Force Base in Tucson and responded to "an interagency call for action" when they moved in to monitor the flight, said Michael Kucharek, a NORAD spokesman.
"We did not intercept nor did we escort (the plane), we merely monitored from the air," Kucharek said.
Authorities in Los Angeles asked Phoenix police to check the possible threat.
Initial reporting indicated it may have been a suspicious device, but authorities wouldn't say where the threat came from.
As the police response continued, flights were taking off and landing only on the southern side of the airport, said Julie Rodriguez, Sky Harbor spokeswoman.
The other runway was closed to departing planes during the investigation.
The investigation also restricted roadway access on the western side of the airport.
Southwest Airlines spokeswoman Katie McDonald said the captain of the flight landed in Phoenix "out of an abundance of caution."