The police also have identified a person of interest in the case, but they are not publicizing his name or giving details about his relationship to Williams.
Gordon revealed that besides the Jordan River, investigators had searched 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. Investigators conducted one of the searches as recently as Wednesday morning, but Lougy declined to say which.
Evidence has been submitted to a local laboratory for forensic testing, but the police are not saying what kind of evidence it is or where it came from.
Lougy said he could not divulge whether Williams was believed to have been staying at the Kearns home or the motor home.Police are still asking anyone who may have any information no matter how minor to call them.
"What solves these cases are people doing the right thing," Lougy said.
While the police hope to find Williams' remains, Lougy pointed out that they have prosecuted cases without a body before.
Police have widened the timeframe 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.
Williams was 25 years old and 6 months pregnant when she vanished, and had an 8-year-old son at home. Police declined to discuss the fate of the child Williams was pregnant with.
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. Before he become a department spokesman, Lougy spent more than three years investigating homicides.
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."
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.
Her family has struggled in the 12 years since as they wondered what happened to the woman they loved and whether she would ever come back.
"There's always that hope that she is going to walk through the door," said sister Lovoina Ortega, who gathered with her family near the banks of the river during the February search. "… If anyone knows anything, just come forward. Whether good or bad. Just give us some closure. [Let us] bring her home and bury her or whatever."
Martin said that his missing stepdaughter was "so cool." She loved playing video games and going camping. He said Williams also struggled with drug abuse, and he believes that may have played a role in the disappearance.
"She wasn't a perfect person," he said, "but she was a real sweet girl."
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.
Gordon mentioned Wednesday that Williams, due to her pregnancy, would have appeared heavier than she looks in the pictures that have been disseminated to the public.
"In these cases, the unknown is really, really hard not knowing where their loved one's at, not knowing what happened to her," Lougy said Wednesday. "This has been a challenging case and has been challenging the family for many, many years. They are very, very hopeful that we can bring some closure for them and hopefully bring her home."
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.