The "suspect in the murder investigation" who has not been named by police or arrested told Vincent details about the woman's death, according to a probable cause statement filed with the jail on Thursday.
But when Vincent was interviewed by police on March 19, he "denied ever speaking to the suspect about this murder investigation," according to the probable cause statement.
The officer who penned the statement wrote that he had interviewed about 25 people during the investigation and has "firsthand knowledge that the suspect ... told [Vincent] about the death of the female," according to the probable cause statement.
According to Utah court records, Vincent was charged with misdemeanor crimes in 1999 and 2003, but both cases were later dismissed. An April 2013 traffic case shows Vincent was, at that time, a resident of Kearns.
Police said last week they had identified a person of interest in the case, but have not publicized that person's name or given any details about his relationship with Williams. Salt Lake City police Detective Cody Lougy said Thursday morning that Vincent is an "acquaintance" of the person of interest, but would not give further details.
Lougy said police have not yet arrested the person of interest or any other person for Williams' murder.
"We're still missing some pieces in this puzzle," he said.
Lougy said police have interviewed 25 witnesses since reopening the case last month, but are still asking for anyone with information about the woman to contact police.
In recent weeks, police searched the Jordan River, as well as another body of water, a home in Kearns, a glass shop in South Salt Lake and a motor home believed to have been involved in the homicide.
Evidence has been submitted to a local laboratory for forensic testing, but the police have not said what kind of evidence it is or where it came from.
Williams was 25 years old and 6 months pregnant when she vanished, and had an 8-year-old son at home.
On Feb. 28, police searched the Jordan River for clues after tips reopened Williams' case. Lougy said at the time that several credible tips led them to the river, but he would not describe the nature of the information.
"We never forget about these cases," he said.
Lougy said crews combed the area near 2590 S. 1160 West for several hours on Feb. 28, with detectives searching on the ground and from above using a helicopter. Divers had searched the river earlier in February but didn't find anything, according to police.
The missing woman's stepfather, Rick Martin, said last month during the river search that he suspected foul play. Martin said the "sweet girl" he knew would never leave her family and not come back home.
"I think somebody did something to her," Martin said. "She wouldn't just disappear and not come back around. Not this long."
Police have widened the time frame for Williams' disappearance, saying it could have been as early as November 2001 or early 2002. They earlier said she was last seen by family members on March 6, 2002.
According to earlier reports, Williams was last seen when she dropped off some belongings at a relative's house and said she would return to the home near 1700 South and West Temple.
Williams' family reported her disappearance in May 2002. She is black and 5 feet 2 to 5 feet 4 inches tall. When she disappeared, she weighed 140 pounds, had pierced ears and a pierced tongue. The name "Shawn" was tattooed on her wrist.
Anyone with information may call 801-799-3000. Anonymous tips may be sent by texting the keyword TIPSLCPD plus any relevant information to CRIMES 274637. The case number is 02-79626.