New developments in the search for Tiffany Sessions

This Sunday will mark the 25th anniversary of the day Tiffany Sessions vanished. Her parents and detectives have spent the entire time looking for any trace of her, and finding nothing.

But now, "48 Hours" correspondent Tracy Smith reported on "CBS This Morning," there's a major development in the case -- one of Florida's most famous missing persons cases.

For the past 5 years, "48 Hours" has been working this story, and now detectives tell CBS News they think they know who killed Tiffany Sessions.

Pat Sessions said, "We all were trying to get a handle on what possible explanation. Did she have a boyfriend nobody knew about? She didn't have her wallet, her driver's license. Her car was there. And that was the scary part."

Hilary Sessions had just seen Tiffany at Christmas one month earlier. 

"She came up to me and she gave me a hug," Hilary Sessions said. "And it was a hug that I’d never had before. And she gave me a big kiss and said, 'Mom I love you'."

Jim Eckert, one of the lead detectives in 1989 said, "This woman literally vanished off the face of the Earth."

In desperation, Pat Sessions, a marketing executive, did what he knows how to do best. He organized press conferences, bought in famous faces like football Hall of Famer Dan Marino and politician Jeb Bush, and he coordinated one of the biggest, private searches in Florida history. More than 700 people showed up, they searched the swamps around Tiffany's walking route, they blanketed the state with fliers, put Tiffany's face on billboards, and answered the hotline.

Tracy Smith remarked: "This was really kind of unprecedented, the amount of attention that Tiffany Sessions got. And yet..."

Eckert said, "No leads. No physical evidence."

Pat Sessions said, "It was pretty obvious to all of us, you know, that we were in a huge problem.  If anything was going to turn up then, it would have turned up in that search."

There were grueling ups and downs for the 20 detectives who worked this case for more than two decades, but for one detective, the time to solve it is now.

Detective Kevin Allen, of the Alachua County Sheriff's Office, said, "I go to bed thinking about that case.  I wake up thinking about that case."

Recently, "48 Hours" learned there is a new development in the case. On Thursday, Allen and his colleagues will announce that they believe Paul Rowles, a known serial killer, is a lead suspect in the disappearance of Tiffany Sessions.

Rowles’ last known victim, Elizabeth Foster, was found just one mile from where Tiffany disappeared.

Right now police are excavating the site where Foster’s body was found, hoping to find Tiffany.

Pat Sessions said, "Twenty-five years ago we started. I hope we're gonna finish."

Asked how long he will look for her, Pat Sessions said, "Well, I think until the day I die. How do you not look for your kid?"

There is one other tantalizing clue -- the serial killer left behind an address book and on one page he scribbled the number 2989, which is the very date Tiffany Sessions vanished. He also put a number 2, which detectives believe means Tiffany was his second victim, Smith added on "CTM."

Asked if there's anything else that ties Rowles to Tiffany, Smith said he was a pizza delivery man in Gainesville, so he could have delivered a pizza to her door and he worked a construction site on the route where she power walked every day.

Rowles was sentenced to life in prison for another crime and he died of natural causes. Smith added that he did not make any deathbed confession, but investigators still believe he's the No. 1 suspect.

If anyone has information about this lead suspect Paul Rowles please contact, Detective Kevin Allen, Cold Case Homicide, 352-384-3323 or email him: kallen@alachuasheriff.org.