The photo, taken in December 2001, is a constant reminder to Waters on why he does his job — conversing with and trying to snare child sex predators who seek out victims over the Internet.

That Santa Claus is now behind bars at the Wyoming State Penitentiary, serving a three-to-five year prison sentence after being convicted of attempted indecent liberties with a child. The man was arrested after Waters and other undercover agents posing as a young girl on the Internet arranged to meet him in the mall.

"This gets close to my family," Waters said. "If it's getting close to mine, it's getting close to a lot of people's."

A special agent with the Wyoming Division of Criminal Investigation, Waters oversees a team of three state agents, a U.S. Customs agent and a forensics investigator inside a one-story, nondescript office just off downtown. One of 45 nationwide set up by the U.S. Justice Department, Wyoming's team has been recognized as an international leader in combating child pornography over the Internet and nabbing child sex predators.

Besides Santa, Waters and the special task force he oversees have helped bust a nuclear engineer, a prosecutor, a firefighter, a NASA rocket scientist, a teacher, and a truck driver. In January, Waters conducted the Internet undercover work that resulted in the arrest of 37 people in New Jersey, including a high school hockey coach and a pediatric neurosurgeon, on child pornography charges.

In 2004, the International Association of Chiefs of Police recognized the Wyoming team for developing software that identified more than 3,600 computers investigated for distributing child pornography. A separate computer program helps investigators organize volumes of data generated by computerized child porn investigations.

"The Wyoming Internet Crimes Against Children task force has made remarkable contributions nationwide with its development of software to help law enforcement apprehend criminals who would prey upon our children through the Internet," said Robert Flores, administrator of the Justice Department's Office of Juvenile Justice and Delinquency Prevention.

A former Army military policeman and street cop, Waters mostly trained himself on computer programming. Now, he trains and advises local, state, federal and international law enforcement agencies how to use the software he's developed to catch — and convict — child porn distributors. A bobby hat on display in his office was a gift from a team in England he trained.

Digital investigations have their own complexities. A suspect's hard drive has to be copied before its contents can be examined, otherwise the suspect can claim the device was tampered with. And then there's the sheer volume of evidence, requiring special software to keep investigators from being overwhelmed.

"When you get in here and identify 1,000 guys a day, it's really a headache to document all that," Waters said.

His latest program speeds up the identification and location of suspected child porn distributors so local police can more quickly obtain search warrants. So far, it has documented more than 225,000 instances of people offering to send child porn.

"We're maxing it out right now, identifying the distributors," Waters said.

Investigators who pose as teens in chat rooms have no problem finding would-be predators. In fact, the predators usually find them.

"We could have 25 guys on a chat room soliciting sex in a matter of 10 minutes," Waters said.

On a Thursday morning in February, Waters sat down at one of the three computers at his work station, logged onto Yahoo with one of his hundreds of chat names — one he wouldn't reveal so as not to blow his cover. He said similar chat rooms run day and night on Microsoft MSN, America Online, Internet Relay Chat and other providers, all of which have cooperated with investigators.

On his screen popped up a list of 100 topics that included such titles as "PAC'S PRETEEN PICS and POSTS," and "INCEST IS BEST."

Within minutes, someone using the name "brutal childbeater" wanted to talk with Waters about abusing a baby — one of 17 contacts he received in less than 20 minutes.

"This job can really make you sick to your stomach," Waters said, scrolling through the written conversation in disgust.

Other similar chat rooms on the site were already so full that Waters couldn't get into them.

Officers often find real children online with predators, but they can't intervene until a crime has been committed, Waters said.

Investigators also must be careful not to appear to entrap anyone — "We don't solicit sex, don't initiate contact," Waters said — but some child predators are so bold, entrapment isn't a problem.

"These guys contact us very quickly," Waters said.

Waters, who doesn't allow his children to use the family's home computer without parental supervision, tries to educate parents about the dangers of leaving their children unattended on the Internet, especially those kids with high-speed Internet access and a Web camera in their own bedrooms.

He knows of no software package that he would trust to protect children from Internet predators, mainly because children are too computer savvy and can easily bypass such safeguards.

If the bearded, 42-year-old Waters had his way, chat room predators would see "every girl and boy as looking like me."