ATLANTA — Authorities apprehended a man at Atlanta’s busy airport on Monday following a tip-off from his family, who reported his intentions to carry out a shooting at the location. Police discovered an assault rifle and ammunition in his truck parked outside, according to the city’s police chief.

Billy Joe Cagle, a resident of Cartersville, Georgia, had allegedly discussed his intention to attack the world’s busiest airport during a social media livestream, Chief Darin Schierbaum announced at a press briefing.

“The Cartersville Police Department received information from Mr. Cagle’s family, who reported that he was broadcasting his plan to head to the Atlanta airport with the intent to ‘shoot it up.’ They also informed us that he was armed with an assault rifle,” Schierbaum explained, noting that Cagle is a convicted felon.

Cagle, 49, arrived at Hartsfield-Jackson Atlanta International Airport driving a Chevrolet pickup truck, which he parked just outside the terminal entrance. Upon inspection, police found an AR-15 rifle along with 27 rounds of ammunition in the vehicle, Schierbaum stated.

“Today, we are able to speak of a successful intervention rather than a tragic incident, thanks to a family who observed something concerning and took action,” the chief emphasized.

Cartersville police Capt. Greg Sparacio, whose department received the initial tip from family members, said Cagle “had the intention to inflict harm to as many people as he could.”

During the news conference, police showed surveillance video that shows Cagle arriving at the airport and body camera video of his arrest.

A Chevrolet flatbed pickup truck is seen arriving curbside at the airport terminal around 9:30 a.m. and then a man police identified as Cagle is seen entering the airport a few minutes later. He walks over to the TSA security checkpoint and had “high interest in that area,” Schierbaum said.

Body camera footage shows Atlanta police officers, who had a photo of Cagle provided by his family on their phones, approach him and start asking him questions before taking him into custody. As they take him to the ground and put handcuffs on him, Cagle can be heard yelling.

Cagle has been charged with making terroristic threats, criminal attempt to commit aggravated assault, possession of a firearm during the commission of a felony and possession of a firearm by a felon, Schierbaum said.

Since Cagle is a convicted felon, Atlanta police will work with federal authorities to determine how he obtained the gun “which he was not able to legally possess,” Schierbaum said.

Mayor Andre Dickens said “we’re thankful to God” that a tragedy was averted.

“We’re thankful to God and to good information, and good intel, and good people for this crisis being averted,” the mayor said.