Investigators have begun interviewing sex offenders who live in the neighborhood where Brianna Denison disappeared from. They say within a one-mile span of the home on Mackay Way, there are about 100 registered sex offenders...and police want to talk to all of them.

Officers checked every empty home, building and alley in the Mackay Way neighborhood, leaving no trash can unturned. With no sign of Brianna, they say their next step was taking a closer look at neighbors with past convictions of a sex crime.

Sergeant Jim Gurley is in charge of Parole and Probation's Sex Offender Unit. He says his unit has monthly contact with the sex offenders they supervise. While his team is not conducting the Brianna Denison investigation, may be able to provide police with key information on clients.

"If we can help in any way, we are open to a phone call and doing whatever we can to help those agencies out," said Gurley.

Brianna's close friend, Nicole Bridges left flowers on the Mackay Way doorstep, begging for her friend's return. She says she knew about the dangers of living in the near-campus neighborhood, even before Brianna disappeared.

"I didn't suspect a specific person, but I know there are sex offenders in this neighborhood. I've googled it. It definitely clicked when it happened, that it could have been someone," said Bridges.

Bridges says she wonders if someone stalked her friend and followed her home, hoping to take advantage of an unlocked door and a perfect target.

"She's tiny. She's gorgeous. I mean, the girl is absolutely drop-dead gorgeous."

Police say the neighborhood sex offender sweep is not an investigation based on a tip or a lead, but just the next step they're taking in a very mysterious disappearance. Police say it's one way to clear the names of those who are innocent.

"It is tough to have that stigma of being a sex offender, no doubt about that. I am sure from their viewpoint it would make it very hard to know there is a website with details of where I live and what I do, but a great majority of these guys are law abiding citizens."

Authorities have set up at 24-hour tip line, so the public can help with the search for Brianna Denison. Anyone who recognizes her or can help, is urged to call 745-3521.