A South Carolina man allegedly strangled his girlfriend to death, only to experience a fatal “cardiac event” while burying the body. Authorities in Edgefield County identified the deceased suspect as Joseph Anthony McKinnon, 60, and the victim as Patricia Ruth Dent, 65.

Deputies said they were called out 10 a.m. on Saturday to Tanglewood Drive in the town of Trenton, according to a report by Augusta, Georgia ABC affiliate WJBF. Two bodies were found in the backyard of a home, authorities said. One of them, Dent, was in what authorities described as a freshly dug pit. She was the victim of apparent foul play.

The coroner determined that McKinnon died of cardiac arrest — or what Sheriff Jody Rowland described as a “cardiac event.”

Citing evidence from the scene as well as witness statements, authorities suggest that McKinnon attacked Dent at the home, then bound her, wrapped her in trash bags, and put her in the pit. But McKinnon is believed to have had the so-called cardiac event while burying Dent.

The duo lived together at the residence, authorities said.

“On Saturday morning Deputies along with the Edgefield County Coroner’s Office, and Edgefield County EMS responded to 102 Tanglewood Drive in Trenton, South Carolina to a call of an unresponsive man lying in his yard,” said Rowland and Edgefield County Coroner David Burnett in a joint statement obtained by WJBF. “Joseph Anthony McKinnon, 60, of the same address was found to be deceased in his yard. Mr. McKinnon had no signs of trauma and natural causes were suspected. While investigating the death and making notifications to the next of kin, a second body, was located in a freshly dug pit. Patricia Ruth Dent, 65, of the same address appeared to have died by foul play.”

McKinnon managed to partially fill the pit before he experienced the “cardiac event.”

Dent was McKinnon’s girlfriend, according to WRDW, who interviewed the slain woman’s twin sister Pamela Briggs.

“I would say a nightmare, and I want to wake up, and it’s a dream,” Dent’s twin sister Pamela Briggs said. “I know it’s not. This is reality and life, and a big part of me is gone, and now I’m going to have to live with that.”

Briggs said she saw no signs that the alleged events were about to happen.

“Everybody who ever met her liked her,” she said. “She was just full of energy. She was 65 and working.”

Man Strangled Girlfriend to Death, Then Had a Fatal ‘Cardiac Event’ While Burying the Body: Sheriff