Joseph McKinnon, 60, killed Patricia Dent, 65, inside a Trenton home Saturday, the Edgefield County Sheriff’s Office said. Deputies responded to the residence over reports of “an unresponsive male lying in his yard,” Sheriff Jody Rowland said in a news release.

When they arrived, they found McKinnon’s body. Medical crews were called to the scene and tried to revive him, Fox Carolina reported.

During their investigation, deputies found a second body in a freshly dug pit, Rowland said. The body was identified as Dent, who lived with McKinnon, authorities said.

He had a “cardiac event” while covering the pit, authorities said. Investigators believe McKinnon attacked Dent in the home. An autopsy determined she died by strangulation.