Police said Vann confessed to the murder of Afrikka Hardy, 19. Her body was found at 9:30 p.m. Friday in Hammond, Ind., at a Motel 6, located in the 3800-block of 179th Street. She had arranged to meet Vann for sex, according to Hammond Police Chief Doughty, and the facilitator of that encounter led officials to Vann after finding Hardy's body.
Vann was arrested near his Gary, Ind., home without incident on Saturday afternoon. He began talking, Chief Doughty said, and told police he "had messed up by committing the crime in Hammond, and was surprised by how quickly he was located."
He was charged in Hardy's gruesome murder on Monday afternoon.
WATCH: Darren Deon Vann charged in the murder of Afrikka Hardy
Vann, a registered sex offender in Texas, led police to the bodies of six other women at abandoned homes in Gary, Ind. Officials said there could be more victims.
"It could go back as far as 20 years based on some statements we have. That has yet to be corroborated," Hammond Police Chief John D. Doughty said. "He's claimed crimes he committed in Indiana go back that far."
Vann lived in Austin, Chicago and Northwest Indiana. Police are checking his movements against their cold cases.
VIDEO: Suspect's ex-wife 'never knew him to be violent'
7 bodies of Indiana women found over weekend
Hardy's body was the first found. She was strangled, according to an autopsy, as were all the other women, officials said.
"I can't tell her I love her anymore. I can't give her hugs. I can't give her kisses. She was supposed to come home for Thanksgiving," Lori Townsend, Hardy's mother, who lives in Colorado, said. "He was a convicted sex offender. Who knows how long he's been doing this? Him, wanting to be caught, and confess. That's only stuff from a movie."
On Saturday at 11:20 p.m., the body of Anith Jones, 35, of Merrillville, was found in the 400-block of East 43rd Avenue. She was reported missing on October 8.
Early Sunday, the body of Teaira Batey, 28, of Gary, was found in an abandoned home in the 1800-block of East 19th Avenue. She was reported missing in late January, according to her boyfriend, Marvin Clinton.
"She would give you anything she had. And she would go without. And that's the kind of person she was," Clinton said. Batey and Clinton have a 2-year-old son.
"That's going to be the hardest part about it. Because he loved his momma. And she loved him. It's devastating," he said.
Another victim, still unidentified, was also found in the 2200-block of Massachusetts Street.
On Sunday evening, the body of Christine Williams, 26, was found in the 4300-block of Massachusetts Street. Hours later, two more bodies were found in the 400-block of east 43rd Avenue. They have not been identified.
"Once we find out who they are, we can do a timeline back to see who the last person was that they talked to or last person was who they were with and then the investigation can really take off," Gary Police Department Cpl. Gabrielle King said.
"It indicates that he preyed on individuals who might have been less likely to be reported missing," Gary Mayor Karen Freeman-Wilson said.
"They're not nobodies. They're somebody. They're somebody's daughter. Somebody's mother. Somebody's sister. My daughter, she was somebody. She was somebody important," Townsend said.
Mayor Freeman-Wilson said there is an ongoing effort to catalog and board-up abandoned buildings like the ones where Vann allegedly dumped his victims.
"We are also in the process of demolishing buildings. But when you have 10,000 buildings, you don't have resources to demolish all of the ones that would be candidates for demolition," she said. "But we anticipate in the next year we will be demolishing 1,000 buildings."
Gary residents agree the buildings need to go.
"They should get rid of them. If they weren't abandoned he wouldn't have had anywhere to put them. His spree might not have been so long," Andrew Johnson said.
Mayor Freeman-Wilson said the city may use cadaver dogs to search other abandoned buildings.
WATCH: Hammond police full news conference