Bruce Mendenhall, 56, has been charged in only one killing but gave statements implicating himself in five others, authorities said.
The Albion, Ill., resident was charged with criminal homicide Thursday after being questioned by police at the same truck stop along Interstate 24 in north Nashville where Sara Nicole Hulbert was found dead with gunshot wounds on June 26.
Police said Detective Sgt. Pat Postiglione went to the truck stop on Thursday to conduct a follow-up interview in the investigation of Hulbert's death.
When he got there he saw a truck fitting the description of a vehicle that was spotted the night before Hulbert's body was found. The detective said the driver, Mendenhall, appeared nervous when being questioned and granted permission to look inside his cab.
Mendenhall was taken into custody when the detective spotted what appeared to be blood inside the cab, police said in a news release.
During questioning, the driver gave a statement implicating himself in Hulbert's death, as well as the death of Symantha Winters, 48, of Nashville, whose body was found June 6 stuffed in a trash can at another truck stop in Lebanon, 26 miles east of Nashville, police said. She also was shot.
Police, who have been investigating whether the two Tennessee slayings were related to each other and a series of other slayings of women across the South, said Mendenhall also implicated himself in one death in Alabama, another in Georgia and two in Indiana.
Details of the alleged slayings in other states, including the names of victims and their locations, were not immediately released.
Postiglione said there is a "pretty good possibility" that Mendenhall could be linked to deaths besides these six, reported the Tennessean.
Mendenhall was in custody and scheduled to appear in court Wednesday. He had not yet retained or been appointed an attorney.
His truck was impounded and was being searched for evidence by the Tennessee Bureau of Investigation.
Authorities in Albion, which is in Edwards County in southeastern Illinois, said they had just learned of the allegations from Tennessee authorities on Thursday night and had not yet been able to investigate Mendenhall's background.
Mendenhall had been driving the truck for Quality Oak Products in Noble, Ill., for about a year, company owner Dan Davis said. Davis said the case was "a complete shock to us."
Davis told the newspaper of Mendenhall, "I didn't see this coming. He is a little slow. He's not well-educated. He wasn't an Einstein, but he was a good worker, very personable, easy to talk to."
"The more news I watch, the sicker I get," Davis said.
He told the newspaper that he last saw Mendenhall more than a week ago at a mechanic's shop where Mendenhall was having his truck repaired.
"I kinda looked into the truck and said 'Bruce, you kinda need to get that truck cleaned out,'" Davis said, adding that Mendenhall promised to clean the cab.