ATLANTA — Federal prosecutors on Tuesday brought charges against a Georgia man who was arrested a day earlier by police after his family contacted authorities saying he planned a shooting at Atlanta’s international airport.

Billy Joe Cagle, 49, threatened to “shoot up” the world’s busiest airport on a FaceTime call while driving, abruptly ending the call after saying, “I’m at the airport, and I’m gonna go rat-a-tat-tat,” prosecutors said in a news release.

Atlanta police arrested Cagle, of Cartersville, on Monday at Hartsfield Jackson Atlanta International Airport and found an assault rifle and ammunition in his truck outside, Chief Darin Schierbaum said.

Federal prosecutors said in a news release Tuesday that they had charged Cagle with attempted violence at an international airport, interstate communications containing threats and being a felon in possession of a firearm.

Cagle’s family contacted Cartersville police, who immediately called Atlanta police, authorities said. Officers at the airport were able to find Cagle at the airport and arrest him within 15 minutes, Schierbaum said.

“Cagle senselessly threatened to do heinous violence to innocent travelers, at the world’s busiest airport, with a high-powered weapon that he had no legal right to possess,” U.S. Attorney Theodore Hertzberg said in the statement.

Online jail records showed that Cagle was being held in the Clayton County Jail on state charges of possession of a firearm by a felon and terroristic threats. Schierbaum said Tuesday that he would be transferred to federal custody.

It was not immediately clear whether the man had a lawyer who could comment on his charges and attempts to reach his family were unsuccessful.

Sgt. T. Jones, who has about six months left in her three-decade career with the Atlanta Police Department, was on the phone with one of Cagle’s family members Monday morning, relaying information to officers to help them identify him. She and other officers spoke about the arrest during a news conference Tuesday.

“This is what I’ve trained to do and I’ve loved doing this for the past 29 years and it’s just an amazing feeling,” she said of helping to avert a potential tragedy.

Officer M. Banks, who has been with the Atlanta Police Department for nearly three years and at the airport for about two years, identified and arrested Cagle.