An argument over a winning $500 scratch-off lottery ticket apparently prompted a man to shoot his live-in girlfriend Saturday morning, then turn the gun on himself, Fort Worth police said Tuesday.

"We received information that the suspect had won $500 on a Texas lottery scratch-off ticket and that the victim wanted half of the proceeds," said homicide Sgt. Joe Loughman. "The suspect didn't want to share it with her."

Though critically injured from a gunshot wound to the chest, 48-year-old Laurice Hampton was able to call 911 about 6:30 a.m. Saturday to report the shootings by Terry Martin, 46.

"She told them that she had been shot and that he had shot himself after he shot her," said homicide Sgt. Joe Loughman.

Loughman said the couple had known each other since childhood and had lived together for several years. They were known to have a "very volatile relationship," he said.