SWANSBORO, ONSLOW COUNTY -

A Vietnam Marine veteran pleaded guilty Monday to shooting and killing a woman in Swansboro early last year.

John Giltz, 67, pleaded guilty to second-degree murder for the death of 50-year-old Susan Zemlick. Her body was found at Giltz's home on South Dogwood Lane on Jan. 23, 2012.

Police said Zemlick was killed by one gunshot. She had lived at the home with John Giltz and his wife since October 2011, when she became separated from her husband. Giltz's family said Zemlick had been a neighbor for a few years.

Prosecutors said Giltz turned himself in after he shot Zemlick.

"I did it; it was not premeditated. I just did it [and] I'll have to pay," Giltz said at the Magistrate's Office. But he never explained why he committed the murder.

According to the defense, Giltz was diagnosed with PTSD, which could have played a role in the incident. Defense attorney William Morgan said Giltz knows his actions were wrong.

Giltz has no prior criminal record. He could get 10 to 13 years in prison.