An Oklahoma man mowed down and killed his mother when she tried to get her car back from him — then tried to slit his own throat when police arrested him for murder, according to authorities.

John Tiffin, 31, killed mom Karen Curthoys, 69, on Oct. 7 when she arrived with another son to confront Tiffin for failing to return the car he’d borrowed from her, according to the Tulsa Police Department.

The mom “stood in the driveway between the car she arrived in and the car Tiffin hadn’t returned” when her other son “opened the car door to confront” John Tiffin and his brother inside, cops said.

During the fight, “Tiffin shifted the car into reverse and hit the gas pedal, hitting his brother with the open door and pinning his mother between the two cars,” the department said.

Karen Curthoys was rushed to the hospital, where she died from her injuries days later.

Tiffin was initially questioned and released, before a judge signed off on an arrest warrant Tuesday.

When officers arrived at Tiffin’s home, he refused to come out, with K-9s eventually finding him in a bedroom.

“Tiffin was holding two knives and trying to cut at his own neck when officers found him,” cops said.

After several commands, he dropped the knives, and police took him to the hospital to be cleared for jail.

Tiffin was covered in blood in his mugshot and a cut is visible on his neck.

He is charged with second-degree murder, assault and battery with a dangerous w𝔢𝔞𝔭𝔬η, reckless driving and obstructing an officer.