SAN DIEGO -- Adam4Adam is the website where Paul's nightmare began.

"In the gay community, it's really well-known and big. I think Adam4Adam tends to be more of a sexual hookup (Web) site," said Paul (name changed to protect identity).

Paul said he came across Timothy Williams' profile on Adam4Adam, a site that caters to gay men.

Williams and Paul chatted via e-mail.

Paul said, "We corresponded like that I think several times before we ever met."

When Paul met Williams, he said he felt there was nothing out of the ordinary, but it did not stay that way.

"I just left the room for a moment and since he had the plan to take something, (he) grabbed my checkbook and ripped a check out of it when I was out of the room," said Paul.

Paul later discovered he was not the only one missing a check.

"Other people had filed complaints. They said, 'Well, what about this check? This is a large check.' And they contacted me to say, 'Did you write this check intentionally?'" said Paul.

Prosecutor Bruce Silva said Williams reportedly stole checks and other items from four people he met on the Web site.

"From at least three of the victims he stole checks, which he then forged, deposited into his account and then drained the accounts," said Silva.

Police said these types of crimes are becoming more common on all social-networking Web sites.

Despite constant reminders, authorities said people still fall prey.

"It's not just petty theft or grand theft that happens in these cases or identity theft. There are circumstances where worst things have happened. We've seen people meet someone on a social networking Web site and disappear," said Monica Munoz of the San Diego Police Department.

Paul said it's a lesson learned the hard way -- you can't ever be too cautious when meeting people on the Internet.

Williams is scheduled to be sentenced on Monday.

There is no word on whether there are more victims.

Authorities said Williams prowled the Internet from September to November 2007.

Paul told 10News that Williams' profile was removed from the Adam4Adam Web site.

There is no word on whether Williams had established any other profiles.