(CNN) -- He seemed a little confused and unsure of his surroundings. Karl Kraus sat alone in a cell, his blue, watery eyes following me as I entered the holding area of a Chiang Mai courthouse. Karl Kraus is 90 years old, hard of hearing, frail and, according to the police, a dangerous pedophile.
I'd wandered into the cells sure I would be rebuffed. Instead, the Second World War veteran seemed keen to talk to me. He explained how the allegations against him are motivated by greedy neighbors. He claimed they are trying to blackmail him. It's an argument he will make to judges in the coming weeks. Karl Kraus is thought to be the oldest person ever accused of child molestation in Thailand's over-burdened penal system.
Last year, 2,888 people were charged with having sex with children under 15 in Thailand. Thailand has become the destination of choice for sex tourists looking to prey on children. But now the police are raising their game, determined to turn the tide.
Police Lt. Col. Apichart Hattasin leads a small but very determined unit of officers in Chiang Mai, all dedicated to tracking down pedophiles.
The workload is going up each month; officers here aren't sure whether that is because they are simply uncovering more cases, or whether more and more pedophiles are choosing to relocate to Thailand.
But Col. Apichart is on a mission to catch them and that's not easy. He opened his files to CNN, showing us dozens of surveillance videos, photos and cases histories of suspected pedophiles. While he and his men may be convinced someone may be sexually molesting children, proving it in court is another matter. Often a case pivots on the testimonies of the young victims and that means defendants are often tempted to buy off families.
"Money can change a lot, it can change even the mind of the victims." he said.
"The suspect might try to approach the victim or the family of the victims, to convince them or give bribery to make them change their statement. And if they change their statement, it could be different or totally different I would say. That is the most challenge".
And Col.Apichart is clear the law needs reform.
"There is no specific law about having child pornography in possession," he said. "Thailand should issue the new law about child pornography specifically".
Ronnasit Proeksayajiva is with a small NGO called the Counter Human Trafficking Unit. He works closely with Col. Apichart, often accompanying officers on raids. His assessment is frank -- and bleak.
"Honestly right now I don't think it is getting better, I think it is getting worse, because I don't know, maybe they believe that Thailand is the best place for them to come to have sex with the children".
Karl Kraus is alleged to have lured girls into his modest rundown bungalow in Doi Saket near Chiang Mai. Just a few houses away, I met the mother of the four girls Karl Kraus is accused of abusing. She denied his claim that she is trying to extort money from him. Instead she breaks down and weeps as she goes into harrowing detail about the ordeal her daughters endured. The youngest girl Kraus is accused of abusing is just seven years old.
Kraus' case has received media attention because of his age, but there are many thousands of other cases in Thailand, which largely go unreported. Like Swiss banker Cornel Wietlisbach, who pleaded guilty to abusing young boys in Chiang Mai -- he was facing a four year sentence, but this was halved because he cooperated with the police. In the end, he was granted parole immediately and was deported back to Switzerland after he'd paid a 4,000 baht fine (about $125).
Such cases do little to discourage pedophiles from coming to Thailand. Col. Apichart says online forums are abuzz with talk about Thailand being a child molesters' paradise.
"There is a group of the pedophiles online, it is a community, they talk with each other and they like to come to a third world country where the criminal justice system is not strong enough to deal with them".
Another case working its way through the penal system is that of Robert Cutler, a U.S. Fulbright Scholar teaching biology at a Chiang Mai University. The police accuse him of sexually abusing young boys, something Cutler denies. Col. Apichart had him under surveillance for weeks. The photos show Cutler talking to groups of young boys on the street and taking other boys swimming at a local pool. A video of a police search of his apartment revealed semi-clothed youths in his bedroom. All this will form part of the case against him, which is due to start later this month.
Col. Apichart has this message to pedophiles thinking of coming to Thailand: "I would welcome them to come here, I'm looking for them and if they think they can escape let's try. I will get them one way or another. I will make sure they get punished".
