DIAMOND, Mo. — No one will ever confuse Jim Murray with a teenager. His tall frame, broad shoulders and clipped gray hair give him away for the grandfather he is.
But the 69-year-old retired police chief of this small Missouri town cuts a credible figure as a 13-year-old girl surfing the Web, looking for friends. He knows all the instant-messaging shorthand, the emoticons.
Murray's retirement job from a rural home office has netted 20 arrests since he started in 2002. His latest catch was the biggest: four felony enticement charges against a town mayor, who after his arrest called Murray up and begged him to make the case go away.
Nineteen other defendants have included a Missouri furniture company executive, an Arkansas professor and a Tulsa, Okla., school security guard. Ten of those men have been convicted and sent to prison. One was deported. The other cases are still pending.
The defendants ranged in age from 24 to 62, with an average age of 39.4 years, and mainly come from Missouri, Arkansas and Oklahoma, Diamond police said.
Internet child safety experts say police officers like Murray are heroes who do good work at the cost of wading through the muck of online pedophile fantasies.
''He's a trailblazer. 2002 was very early for smaller police departments to start doing this,'' said Parry Aftab, executive director of Wiredsafety.org, a children's Internet safety group.
Murray, who taught elementary school for 27 years before switching to police work, is more humble.
''This is really about the kids,'' he said.
The first thing he hands a reporter at the start of an interview is a neat packet of newspaper stories about Kacie Woody, a 13-year-old girl in neighboring Arkansas who was abducted, raped and killed by a man she met online. It's not a case Murray worked on. Instead, he said, it's ''a motivator.''
Murray said he manages to shake the online conversations out of his head after a while, but they can still make him angry.
''There'll be times when you just want to reach through the screen and choke them or slap them,'' he said. ''To think they could talk that way to a girl.''
The latest defendant is Allen Kauffman, 63, who resigned as mayor of Collins and pastor of Temple Lot Church after he was arrested Jan. 11 at home in his small town about 110 miles southeast of Kansas City.
Kauffman declined Wednesday to discuss the specifics of his case, including how he plans to plea and his lawyer did not return a phone message.
Kauffman did not propose an actual meeting in any of the exchanges listed in the charging documents.
But according to court documents, prosecutors say Murray was logged into a Yahoo! chat room as a 13-year-old girl named ''cindyndiamond'' using the screen name ''Cin'' when he was first contacted Nov. 15 by ''duke dukead,'' who prosecutors allege was Kauffman.
Duke contacted Cindy again the next day and said he was 55 years old. The exchange included:
Cin: i like to french kiss ... senior boy taught me.
duke dukeadk: but it depends on where you want to be kissed at lol.
In at least five instant-message sessions through mid-December, Duke allegedly went on to tell Cindy he wanted to have sex with her, asked for nude photos of her and suggested Cindy have sex with another girl in front of a Webcam so that Duke could watch.
Murray has arrested other men arriving for trysts they believed they were setting up with the detective's teenage persona.
Murray was chief of police in the farm town of Diamond from 1995 to 2000. He got a personal computer after retiring and discovered chat rooms and was angered when he was offered pictures of young girls.
He contacted experts in the field of Internet sting operation and got training from the National White Collar Crime Center on basic computer data recovery.
Now, Murray patrols the Web from a cramped home office divided between his police computer and a personal computer ringed with photos of his six grandchildren and three adult kids.
Murray remains a detective on reserve status with the Diamond police but he donates his investigation time. He says he only spends about 30 minutes a week on average in chats but several hours more going over hard drives of arrested suspects looking for contacts with other potential victims.
''Several people have stopped me at Wal-Mart and the filling station and said they appreciate what we're doing on the Internet stuff. And that's a good feeling.''