Crime Man Dies of Heart Attack While Trying to Bury Girlfriend's Body After He Murdered Her: Sheriff Police say Joseph McKinnon strangled Patricia Ruth Dent, then died of a heart attack while burying her body in his yard By Jeff Truesdell Published on May 11, 2022 03:56 PM Share Tweet Pin Email A South Carolina man is dead after a sheriff says he collapsed from a heart attack while digging a pit to bury his girlfriend after killing her. Joseph McKinnon told a neighbor in Trenton, S.C., that the hole he was creating in his yard was meant for a water feature to enhance his garden, Edgefield County Sheriff Jody Rowland tells PEOPLE. But when a different neighbor subsequently spotted McKinnon, 60, laying face-down and motionless beside the pit on Saturday morning, police were called. "We get there and determine that he apparently has had a heart attack," Rowland says. "No trauma to his body." With no one else at the home, deputies set out to locate and alert McKinnon's next of kin. "However," he says, "we had a hard time finding his significant other." Want to keep up with the latest crime coverage? Sign up for PEOPLE's free True Crime newsletter for breaking crime news, ongoing trial coverage and details of intriguing unsolved cases. Getty Authorities searching for McKinnon's live-in girlfriend, Patricia Ruth Dent, 65, tried to reach her at her workplace, only to learn that her co-workers had been texting Dent with no response since 7:30 a.m., "which was extremely not like her," Rowland says. "Everybody was already concerned before we even got there." Deputies returned their focus to the couple's residence. "We continued to investigate the yard and this huge garden," Rowland says. "The house had been freshly cleaned, but we were able to identify blood in the house that tested as hers." "That took us back to the pit he was digging." "We got down in the pit and started digging around," he says. "We uncovered it enough that we found black garbage bags." When opened, the bags revealed a body bound with tape, and a forensics team was called in. "It really took off then," says the sheriff. Deputies tracked down eyewitnesses to compile a timeline of the couple's last hours, and on Monday learned the results of autopsies performed on the pair. "We were very certain of what we thought had happened," Rowland says, adding that the autopsy results filled in the gaps. "She had been hit in the face, but that was certainly not a death blow," he says of Dent. "The autopsy proved she had died of strangulation. His autopsy proved he died of a massive heart attack." The sheriff theorized that after killing Dent, McKinnon bound her with tape before wrapping her body in two large trash bags and dragging it through the house to his truck, which he drove to his garden, where he'd previously dug the pit. The truck was still parked in the garden when deputies showed up. "Apparently he had been covering the hole, which didn't make sense to a witness," Rowland says. "He was feverishly covering the pit, and so we just kind of put things together." "He attacked her, killed her, put her in the pit, and he died covering her up." Rowland says the incident registers as "very out of the ordinary, very unexpected." He knew of no history of domestic abuse between the couple, and said his department had logged no previous incident calls to the Tanglewood Drive address. "Basically," he says, "this case is over."