An ex-NFL player’s mistress kidnapped his wife and shot her to death before turning the gun on herself, police said.

Lisa Brown, the 49-year-old mistress of former Buffalo Bills tight end Buster Barnett, was being pursued by Georgia cops on Thursday when she stopped in the middle of the highway, shot 58-year-old Sandra Barnett and then committed suicide.

Police said Brown was upset about a trip the Barnetts had planned together, according to the Atlanta Journal-Constitution. After confronting Buster at his place of business, Brown sought out Sandra, a middle school special needs teacher.

“She had said, ‘Open this door or you will die. Open this door’”

- Ruby Chester

Sandra was on the phone with a friend, Ruby Chester, when Brown approached her house.

“I knew by the sound of her voice that something was wrong,” Chester told MyFoxAtlanta. “She had said, ‘Open this door or you will die. Open this door.’”

Chester called a co-worker to check on Sandra, and when he arrived, according to a police report, he spotted a suspicious woman on the premises. The co-worker called police, but Brown and Sandra were gone by the time cops showed up.

When police finally caught up to Brown’s SUV, she led them on a high-speed chase that ended in tragedy just over the Alabama state line.

Brown’s home and Dodge Durango were both in Buster’s name, a police spokesperson told the Journal-Constitution.

“Lisa Brown was actually on probation for kidnapping out of the state of Texas,” cops told NBC affiliate 11Alive. “She had kidnapped her child that she had lost custody of, and the jurisdiction down there had to track her for like three days to find her.”

An 11th-round draft pick for the Bills in 1981, Barnett played in 56 games with Buffalo, from 1981-1984. He started eight games, catching 26 passes for 236 yards and one touchdown.

The Associated Press contributed to this report.