Ian Finlay of Shadyside, a former computer security expert at Carnegie Mellon University's CERT Internet policing center, told a Westmoreland County jury yesterday that he was baiting state police in the summer of 2003 when he solicited a 15-year-old Latrobe girl for sex in online chat rooms and e-mails.

After exchanging more than 60 sometimes-explicit e-mails with a policeman posing as "Kelly," Finlay was arrested outside a McDonald's restaurant in Hempfield Aug. 22, 2003, where the "couple" had agreed to meet for sex. He was charged with 10 counts of illegal contact with a minor, one of attempting to commit involuntary deviate sexual intercourse, and one of attempted statutory sexual assault.

His trial opened Tuesday in Greensburg.

Finlay, 28, said he knew police were then training at Edinboro University on how to pose as girls and nab child molesters who solicit youngsters for sex on the Internet. He decided to pull a prank on the police, he said.

"I always had a real dislike for cops," he told the jury. "I can remember sitting there writing, thinking there's a big fat cop sitting there on the other end with doughnut crumbs dribbling down his suit, seeing what I'm writing and spitting out his coffee."

The running joke helped him work out frustration and aggression stemming from marital difficulties, depression and his high-pressure job, he said. He knew "Kelly" was a law enforcement agent because the computer account she used was easily traced back to the state of Pennsylvania, Finlay said.

"I wanted to outsmart the cops. It was ridiculous, I know," he said. "I am by no means a child predator. I could never harm a child that way."

Prosecutors said Finlay's trip to Hempfield is a strike against him, proof he intended to follow through with the rendezvous.

Finlay said it was "the end of everything, the moment when I sent the train off the tracks and put an end to the pressure and the job."

Finlay said he was relieved to be arrested, that he didn't care about consequences beyond the pain his wife would feel at his "putting an end to all the dreams we'd built together."

In her closing argument, Assistant District Attorney Kelly Tua Hammers asked why a man who lied to his wife and employer would bare his soul to someone he knew was a policeman.

"He gave [Kelly] his real name and picture and phone numbers because he wanted to get some action with a 15-year-old girl. And to do that, he had to gain her trust," she said. "He said he was upset that arresting officers robbed him of the opportunity to walk into McDonald's and tell them 'gotcha.' It seems to me he was shocked and amazed to find it was the other way around, that the police got him first."

The jury began deliberations yesterday afternoon.