Todd Kohlhepp, 30, was charged with four counts of murder on Sunday and is suspected of killing as many as seven people after police found a woman "chained up like a dog" on his property.
Kohlhepp confessed to killing four people at Superbike Motorsports in Chesnee, South Carolina, exactly 13 years ago, The Greenville News reports.
Three bodies have been found on Kohlhepp's property since Kala Brown was found alive but in chains on Thursday. One of the bodies was identified as Brown's boyfriend, Charles David Carver.
Kohlhepp is a real-estate agent and a registered sex offender. He was convicted of raping a 14-year-old girl when he was 15 and served 15 years in prison. He lied about his conviction to get the job, Spartanburg County Sheriff Chuck Wright said.
It's all so gruesome that it's a little hard for anyone even veterans to imagine the magnitude of what we're dealing with.
He lives on a 95-acre property near Woodruff, S.C., which be bought in May 2014. Two bodies on that property have not been identified.
Brown said she saw Kohlhepp shoot Carver.
WATCH | Wright said on Saturday "we're not done here yet." They said only about 30-40 percent of Kohlhepp's property had been searched at that time.
We want to see the face. I want to look at him, and I want to try to use that in healing.
The 2003 shootings stunned the town. Rumors of the reason for the killings ranged from Mexican drug gangs or a love triangle gone wrong.
Tom Lucas, whose son Bryan was killed in the 2003 shooting, said seeing Kohlhepp in court would bring "healing."
WATCH | Earlier in the investigation, Wright called the incident "stuff you see in the movies."
The Associated Press contributed to this report.