Former NFL player Phillip Adams has fatally shot five people including a prominent doctor, his wife and their two grandchildren before taking his own life, authorities say.
York County Sheriff Kevin Tolson told a news conference that investigators had not yet determined a motive in the mass shooting on Wednesday.
"There's nothing right now that makes sense to any of us," Tolson said on Thursday.
Dr Robert Lesslie, 70, and his wife, Barbara, 69, were pronounced dead in their home in Rock Hill on Wednesday along with grandchildren Adah Lesslie, 9, and Noah Lesslie, 5, the York County coroner's office said.
A man who had been working at the Lesslie home, James Lewis, 38, from Gaston, was found shot to death outside. A sixth victim, Robert Shook, 38, of Cherryville, North Carolina, was flown to a Charlotte hospital, where he is in critical condition.
At Thursday's news conference, Tolson played audio of two emergency calls, the first from an HVAC company that employed Lewis and Shook. One of them, the caller said, had called him "screaming" and saying he had been shot, and his coworker was shot and "unresponsive".
Tolson said evidence left at the scene of the shooting led authorities to Adams as a suspect. He said they went to the home of Adams' parents, helped them leave then tried to talk Adams out of the house. Eventually, they found him dead of a single gunshot wound to the head in a bedroom, he said.
Tolson said both a .45-calibre and 9mm weapon were used in Wednesday's shooting.
A person briefed on the investigation told the Associated Press that Adams had been treated by Lesslie, who lived near his parents' home, but Tolson would not confirm this.
Adams, 32, played in 78 NFL games over five seasons for six teams. He joined the 49ers in 2010 as a seventh-round draft pick out of South Carolina State, and though he rarely started, he went on to play for New England, Seattle, Oakland and the New York Jets before finishing his career with the Atlanta Falcons in 2015.
As a rookie late in the 2010 season, Adams suffered a severe ankle injury. He never played for the 49ers again, getting released just before the 2011 season began. Later, with the Raiders, he had two concussions over three games in 2012.
Whether he suffered long-lasting concussion-related injuries was not immediately clear.
Adams' father told a Charlotte television station that he blamed football for problems his son had, and which might have led him to commit Wednesday's violence.
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