GAINESVILLE, Fla. -

On the 25th anniversary of the disappearance of Tiffany Sessions, Alachua County Sheriff Sadie Darnell says it's "highly highly probable" that Paul Rowles -- a man who died in prison one year ago doing time for murder, kidnapping and sexual battery -- was responsible for the disappearance of the 20-year-old college student in 1989.

"Come forward if you were involved," Darnell said in a Thursday morning news conference.

"We need the public's help. We are looking for a very small needle in a very big haystack," said Hilary Sessions, Tiffany's mother. "We just need one tip."

The Sheriff's Office invited the media to the site where authorities are digging for new evidence, where they released details of the investigation, case photographs and information regarding the suspect in hopes that disclosing it will result in leads from the public that may help solve the case.

Session's father, Patrick Sessions, a prominent South Florida real estate developer, used his connections with former Miami Dolphins quarterback Dan Marino and other NFL players to gain attention to the case, but his daughter was never found.

Rowles (shown in Florida Department of Corrections photo) was 64 when he died in February 2013 while in state custody. According to Patrick Sessions, Rowles was in Gainesville working as a pizza delivery man and for a construction company in the city at the same time Tiffany Sessions and another woman whose body was recently discovered lived there.

"This is proof that there are evil men among peaceful people, Gainesville Mayor Ed Braddy said.

Patrick Sessions is hoping that if his daughter's remains are recovered, DNA will point toward a killer, or that Thursday's announcement will jog someone's memory about Tiffany's disappearance.

The Sheriff's Office set up a special number for tips in the Session case: 352-955-1818.