A South Carolina man died of a heart attack over the weekend while digging a grave in the backyard for the woman he had just killed.

Deputies in Edgefield County were sent to a home in Trenton on Saturday on a report about “an unresponsive male lying in his yard. Upon arrival they found the body of Joseph Anthony McKinnon, who lived in the home, according to the News & Observer.

Then they found a second body “in a freshly dug pit.” The body was identified as Patricia Ruth Dent, 65, who also lived at the home.

An autopsy revealed that Dent died of strangulation. Investigators believe McKinnon attacked and killed her.

“Mr. McKinnon then bound her and wrapped her in trash bags before putting her in the previously dug pit,” the sheriff’s office said.

McKinnon was in the process of filling pit where he’d dumped Dent’s body when he had a “cardiac event,” investigators said, and died.

Investigators aren’t sure about the relationship between Dent and McKinnon.

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