A prominent South Carolina doctor who was one of five people allegedly gunned down by former NFL player Phillip Adams on Wednesday had stopped giving him medication, which triggered the killings, according to officials. 

In an interview with WBTV News, U.S. Rep. Ralph Norman, R-S.C., said he was told by law enforcement officials that Dr. Robert Lesslie had treated Adams, possibly proving a motive for the bloodshed. 

"My understanding, he was treating him, and had, from my understanding, stopped giving him medicine, and that’s what triggered the killings," Norman said, citing law enforcement.

Phillip Adams during a 2011 NFL game. (Tom Szczerbowski/Getty Images)

Norman was a close friend of the Lesslie family. 

Adams forced his way into Lesslie's Rock Hill home and killed the 70-year-old doctor, his wife, Barbara Lesslie, their two grandkids, ages 5 and 9, and an air conditioning contractor, James Lewis, 39, before killing himself, authorities said. Another air condition tech was wounded and flown to a hospital. 

Lewis was working at the home when he was struck by the gunfire. A 45-caliber and 9mm weapon were used in the shooting, authorities said. 

Earlier, York County Sheriff Kevin Tolson said investigators had not determined a motive for the killings. 

"There's nothing right now that makes sense to any of us," he said.

This March 12, 2009 file photo shows Dr. Robert Lesslie in Rock Hill, S.C. (John D. Simmons/The Charlotte Observer via AP) (AP)

Adams, 32, last played in the NFL with the Atlanta Falcons in 2015. He was a seventh-round pick of the San Francisco 49ers in 2010. He then played for the New England PatriotsSeattle SeahawksOakland Raiders and New York Jets. He career was plagued by injuries, including concussions and a broken ankle.

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His agent, Scott Casterline, told The Associated Press that the former defensive back "was lost without football."

"We encouraged him to explore all of his disability options and he wouldn’t do it. He would isolate, but that’s who he was, so it wasn’t a big concern," Casterline said. "I knew he was hurting and missing football, but he wouldn’t take health tips offered to him. He said he would but he wouldn’t. I felt he was lost without football, somewhat depressed, but he was really hard to follow because he would isolate."

"This is so unlike him," he added. "He had to not be in his right mind, obviously. All of us who knew Phillip are shaking our heads. He struggled away from the game. I tried to get him to come to Texas. I was going to find him a job, but he wouldn’t leave South Carolina because he had a son. He was a good father. Seeing Phillip shoot two kids, it’s not him. I can’t fathom it. It’s devastating for the victims and the families."

Fox News' Ryan Gaydos as well as The Associated Press contributed to this report.