CLEVELAND, Ohio -- Retired Cleveland police officer Robert Bonness described his collection of nearly 100 videos and photos of child pornography as a curiosity -- an interest that he now knows he was wrong to indulge.

But the 23-year veteran of the force used his police training in pursuit of his hobby, installing computer software he learned about while carrying out a child pornography-related search warrant and setting up counter-surveillance to outwit police as he planned a sexual tryst with someone he believed was a 12-year-old girl.

For that, the 53-year-old Parma man was ordered to spend the next 52 1/2 years behind bars with the kinds of criminals he once helped take off the streets.

Cuyahoga County Common Pleas Judge Peter Corrigan sentenced Bonness on Friday. The defendant had pleaded guilty in January to 25 counts, including attempted rape, multiple counts of pandering sexually oriented matter involving a minor, illegal use of a minor in nudity-oriented material or performance, and possessing criminal tools.

Bonness also was ordered to pay a $15,000 fine and is labeled a Tier III sex offender, which requires him to register his address every 90 days for life.

Assistant County Prosecutor Frankie Goldberg told the court that Bonness maintained a vast collection of pornography, featuring children as young as 5 and some engaged in incestuous sexual conduct. But his interest in pedophilia transcended visual images when he responded to a Craig's List ad that he believed was placed by a man looking for a "special person" to spend time with his 12-year-old daughter.

The ad sparked months of communication between Bonness and the father, who actually was a detective in disguise. And Bonness brazenly requested in e-mails the kinds of sexual contact he hoped to have with the juvenile, Goldberg said, quoting the e-mails in court.

Bonness was arrested on Oct. 28, when he drove to a shopping mall to meet the father and daughter and arrange the sexual encounter. In his car police found condoms, lubricant, sex toys, and a jar of caramel.

"Not for a latte, is it Mr. Bonness?" Goldberg shouted at the defendant, who silently hung his head.

Goldberg said 10 victims from Bonness' videos were identified by the National Center for Missing and Exploited Children.

"I'm outraged, we all should be," Goldberg said. "These are our young people. We should do whatever it takes to protect them."

Bonness' lawyer Edward LaRue pleaded with Corrigan for mercy on behalf of his client, who he said faithfully served the public for decades as both a police officer and member of the military.

He argued that a heavy sentence demeans the severity of the crimes committed by repeat offenders. And he said Bonness -- as both a child-victim sex offender and a former cop - will be vulnerable and targeted by fellow inmates in prison.

"Each hour he spends in prison will be like a year based on that fact," LaRue said. "This might be the first double-trouble problem of that sort that this court has ever had to contemplate in terms of what actual hard time this man will have to face."

When given a chance to speak, Bonness begged for mercy, too, and apologized for what he called "stupidity in following my rotten curiosity."

"I have no excuse or reasons for the actions that placed me before you today," he said. "I crossed the line. For that I am eternally sorry, and I embarrassed myself, disgraced my family and dishonored my badge."

Corrigan, before delivering the sentence, said Bonness knew what would happen to him if he went to prison as a former police officer and still was not deterred. That, the judge said, demonstrates the depth of his perversion.

"You may say, 'Well, I was just looking at photos or movies. How is that hurting anyone?'" Corrigan said. "But the actual children in those videos or photos could describe how that will effect them for the rest of their lives. It's a life sentence for them. They understand, as they get older, the scope and breadth of the Internet. And their victimization continues."