Here is a local article detailing Why they arrested Karr:
www.9news.com
9NEWS learns reasons for Karr arrest
KUSA - Thailand police arrested John Mark Karr after seeing him with a young girl sitting on his lap in a school, a source told 9NEWS.
The arrest came after an escalating exchange of e-mails and contacts with Karr, who was using an online alias.
Karr, corresponding as "Daxis" with University of Colorado Professor Michael Tracey, said that the girl reminded him of JonBenet Ramsey, and that he had the same feelings about her as he had about JonBenet.
"He was falling love again" with the girl, the source said.
After being apprehended, Karr claimed to have been at the Ramsey home when JonBenet was killed, and told a source that he gained entrance into the Ramsey house using a basement window. He denied he used a stun-gun.
Karr also told authorities that the garrote on the girl's neck was actually a necklace, the source told 9NEWS. And in his own words, he says he escaped the same way he entered, using a suitcase to get out the window.
Karr became the target of a lengthy investigation last May after he began writing Tracey as Daxis four years ago.
According to sources, this was an erratic correspondence, and ceased altogether for a year. The Daxis e-mails at first were filled with simple curiosity, but eventually became focused on JonBenet, and revealed an obsession with her murder.
In May, his last two e-mails to Tracey, Daxis stated he had been "with her" and that he and someone else were there and "they killed her."
He added "I did it" five or six times. By then, the e-mails were being read by Boulder District Attorney Mary Lacy.
When Lacy first heard about the e-mails, according to the source, she made the decision to look at them. Lacy reportedly told Tracey she would start an investigation on Daxis. The DA investigators first concentrated on the origin of the website and the location of the writer, which proved a problem because the Web site is in Canada.
Despite inquiries by Canadian Mounties, the FBI, United States and Canadian State Departments, and Canadian police, the host Web site wouldn't agree to help in the probe.
After two months of trying to trace the origin of the e-mails, Lacy's office decided to try a different tact. At that time, investigators decided they would see if Daxis would call Tracey.
There were reportedly a number of calls, recorded by the DA's office. These recordings, which amounted to three to four hours, included a minute by minute description of how Daxis said he killed JonBenet.
The frequency of the e-mails increased, coming daily, and at times, several times a day. Some were very short, while other were lengthy and revealed more confessions.
The DA's office then suggested that Tracey mail a picture of Patsy and JonBenet Ramsey that he had for Daxis. The picture was mailed to a UPS office in Bangkok, Thailand. That was two weeks before Karr was arrested.
Thailand police set up surveillance on the UPS office. A man on a mountain bike picked up the letter and picture. Daxis had previously e-mailed he rode a mountain bike. The Thai police then tracked him to a hotel.
Boulder DA investigator Mark Spray was sent to Thailand ten days before the arrest.
It was then they found out the man's name was John Mark Karr and found outstanding warrants for him for child pornography in California. But the investigators still did not know where he went during the day.
Spray and the Thai police joined up for the surveillance, and in one foray, Spray ended up running four miles in traffic after the police vehicle was trapped in a Bangkok gridlock.
They learned Karr worked as a second grade teacher, and that allowed them to make the arrest.
