After 10 years of speculation surrounding the brutal slaying of JonBenet Ramsey, the event that eventually led to the first arrest in the case came down to a chance encounter between a runner and a drifter outside a bookstore in Paris.

Michael Sandrock, a 48-year-old author, journalist and runner, said he bumped into John Mark Karr outside a bookshop called Shakespeare and Company in June, 2002. They struck up a conversation.

Timeline: The JonBenet Ramsey Murder Investigation

It put in motion a sequence of events that would lead to Karr's 4-year e-mail exchange with Sandrock's friend, University of Colorado professor Michael Tracey. The correspondence culminated in Tracey turning over a suspicious passage to prosecutors in May and ultimately Karr's arrest in Thailand this week.

Karr, 41, was escorted to Bangkok's international airport Sunday for a flight to the United States. He is scheduled to fly to Los Angeles and is to end his journey in Boulder, where he faces charges of first-degree murder, kidnapping and child sexual assault.

Karr seemed like a normal fellow in 2002, friendly and well-groomed, Sandrock said. But he was obsessed about who killed 6-year-old JonBenet at her parents' home in Boulder six years earlier, Sandrock said.

"I said I worked for the Daily Camera in Boulder and John Karr got real interested. ... I didn't think it was real strange at that time because so many people ask about the Ramsey case," he said Saturday.

Karr seemed to know a lot about Boulder, and Sandrock said he assumed Karr had visited.

But something was strange about the man Sandrock knew only as "John." Sandrock said the man almost always wanted to talk about JonBenet during the few days they knew each other, and he seemed to know every detail and fixate on the lurid death of the child beauty queen — who was strangled and had a fractured skull.

"I just started getting a real uncomfortable feeling, because it was just too much," he said.

Sandrock said Karr's interest intensified when he learned Sandrock was friends with Tracey, who produced three documentaries on the case and believed JonBenet's parents, John and Patsy, were unfairly suspected for a slaying he believed should be blamed on an intruder.

As the conversations intensified, Karr seemed to be holding back, smiling knowingly as he prodded Sandrock to speculate on who had done it.

"I said something about the intruder, and he kind of smiled a little bit," he said. "I always had a feeling if I had pursued it more, he was ready to tell me something. He needed to definitely talk to someone."

Back home in Boulder a month later, Sandrock found an e-mail from Karr waiting for him. And then another, asking to be put in contact with Tracey. Sandrock forwarded the messages to Tracey, along with a warning of Karr's intensity.

Years of messages continued back and forth. Sandrock said he gathered Karr, who seemed well-educated and intelligent, had "some kind of chess game going on" with Tracey.

When he saw Karr's picture this week and learned of the arrest, Sandrock said he wasn't shocked.

"I was surprised that he got caught because I got the impression from Professor Tracey and him that he's a real intelligent guy," Sandrock said.

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