(CBSDFW.COM) – The FBI has swept an American Airlines M-D 80 twice and agents say there were no hazardous materials found on the plane.

READ MORE: North Texas Man Struck By Former Lake Worth Police Officer Files Federal Lawsuit Against Him

Crews unloaded the passengers’ luggage, and they towed the aircraft back to the terminal.

The bomb threat was phoned in to Austin police just before 7 o’clock tonight. The threat was made against flight 10-72 from Austin.

An airport spokesman says they immediately cordoned off gates A-19 and 20 and shut down one security checkpoint. Then they towed the plane to a remote area.

READ MORE: Police Identify Oscar Rosales As Suspect In Texas Deputy Constable Charles Galloway Slaying

While the luggage stayed on the plane, most of the passengers had gotten off by the time the threat came in.

A spokesman says authorities may want to interview passengers.

“As you know, being a connecting airport, people come here from everywhere. They go everywhere and so many of the passengers could be on connecting flights, they could be airborne already.  So it’s not easy to track all these folks down,” said David Magana, DFW airport spokesman

All airport operations have now returned to normal.

MORE NEWS: North Texas Judge To Decide In Day Or Two Whether To Keep Oath Keepers Founder Stewart Rhodes Jailed Until Trial

Also Check Out: