Jerry Buck Inman, 35, was arrested late Tuesday night in Dandridge, Tenn., where he said he lived with his mother. DNA from the victim's apartment led authorities to him.
"He's made admissions" of an attempted rape in Rainsville, Ala., and a rape in Sevierville, Tenn., both a few days before the Clemson killing, said David Davenport, sheriff of Jefferson County, Tenn. "He said he was out and driving around."
Inman faced charges Wednesday in South Carolina, where 20-year-old Tiffany Marie Souers was raped and killed in her off-campus apartment. Souers, a civil engineering student, was wearing only a bra when found on the bedroom floor May 26. The bikini top was around her neck. Her wrists and ankles were bound.
Inman's DNA matched samples taken from the crime scene, said Robert Stewart, head of South Carolina's Law Enforcement Division. He said a car of the same model and year of one owned by Inman was spotted trying to get money from an ATM near the apartment.
Inman told a judge in Tennessee Wednesday that he wouldn't fight extradition to South Carolina to face charges in Souers' death.
Davenport said South Carolina police called him Tuesday because Inman had registered as a sex offender in Dandridge after his September 2005 release from a Florida prison where he served 18 years for sex offenses. Inman is also a registered offender in Florida and North Carolina.
All states have online registries of sex offenders but more than 100,000 offenders nationwide fail to register or update their addresses, according to the National Center for Missing and Exploited Children.
In Souers' case, the registries did not prevent her murder but helped law enforcement catch a suspect quickly and possibly avoid further killings, said David Finkelhor, director of the Crimes Against Children Research Center at the University of New Hampshire.
Repeat sex offenders who attack adults often target strangers who fit into a fantasy they've created, said Fred Berlin, associate professor of psychiatry at the Johns Hopkins University School of Medicine in Baltimore. They have powerful cravings that sometimes can be controlled but never go away, Berlin said.
Inman's mother, Vera McArthur, told The GreenvilleNews her son is bipolar and often suicidal. She could not be reached for comment.
Davenport said Inman appeared to know right from wrong. "He knew what he was doing."
Contributing: The Associated Press