Centreville — Little more than a year ago, Oak Hill resident Robert C. Fenn was about to finish his first year of teaching at Poplar Tree Elementary, where he taught special-ed students in kindergarten through third grade.

But it all ended June 12, 2012, when Fairfax County police arrested him at the school on child-pornography charges. Last Friday, June 21, the slight-built man with curly hair, thick glasses and wearing a green, jail jumpsuit, stood in federal court in Alexandria to learn his fate.

Although Fenn continued to proclaim his innocence, he’d had a jury trial, April 2-3, in U.S. District Court in Alexandria and was found guilty April 4 of one count each of possession and receipt of child pornography. And on Friday, Judge James C. Cacheris sentenced him to 10 years in prison.

“Possession of child pornography is a serious offense,” said Cacheris. “People watch it online and victimize the child again, causing more harm to that child.”

Fenn had been a substitute teacher with Fairfax County Public Schools since 2009 and was hired full-time in the summer of 2011. His arrest culminated a week-long, joint investigation by members of the police department’s Child Exploitation Unit and U.S. Immigration and Customs Enforcement’s (ICE) Homeland Security Investigations (HSI) agents.

Police charged him with 10 counts of possession of child pornography. Afterward, the school system suspended him without pay and assured parents that no images of students were found on his computer and no school computers were used.

Authorities said Fenn’s online activity was uncovered after he accessed a particular, child-pornography Web site that was being investigated by Italian law-enforcement officials. His case was then taken over by the federal government for prosecution.

On Dec. 6, 2012, he was indicted by a grand jury in U.S. District Court in Alexandria on one count each of possession and receipt of child pornography. The indictment stated that he received this material between March 3, 2012 and May 6, 2012 and further possessed such pornography on June 12 of that year.

Then came his jury trial, this spring, with Fenn, now 27, returning to court last week to receive his punishment. At the outset, his attorney, William Rhyne, noted that the mother of a former student of Fenn’s had written the judge a character reference on Fenn’s behalf.

Rhyne then asked Cacheris to depart downward from the state sentencing guidelines of as much as 11 years, 3 months and give his client no more than the five-year mandatory minimum sentence for his offenses. “He has no record,” said the attorney. “He was an autism, special-ed teacher, and he did nothing to connect his school, its children or equipment [with his personal behavior].”

“The ‘victims’ were victims in other cases,” said Rhyne. “Their parents and step-parents took their photos. So [Fenn] should be treated individually, not as one of many who viewed these images.”

Furthermore, said Rhyne, “He didn’t intend to distribute them or solicit others to view them. Robert’s life would already be ruined because he’ll never be a teacher again, he’ll be on the sex-offender registration, he’ll receive substantial supervision and he’ll have five years in prison.”

But Special Assistant U.S. Attorney Alicia Yass disagreed with Rhyne’s request for leniency. “The sentencing guidelines do take into account the fact that [Fenn] wasn’t communicating with others,” she said. “But the behavior was escalating to the point where he eventually could have become a danger to others.”

Yass said Fenn had gone from doing one or two downloads of child pornography a month to several each month. So, she said, “A guidelines sentence is appropriate — particularly since this defendant hasn’t accepted responsibility — so the behavior is unlikely to change. That’s also why the government is requesting a lifetime of supervised release.”

Before sentencing, Fenn again stated his innocence and said, if given another chance, “I’d avoid looking at pornography.”

The judge then sentenced him to a decade behind bars on each charge, running the sentences concurrently for 10 years total. Cacheris also placed Fenn on 20 years supervision following his release from federal prison. But he warned Fenn that his freedom would be contingent upon his complying with a multitude of conditions, including:

Submit to polygraph testing and a sex-offender therapeutic program; undergo mental-health, psycho-sexual and sex-offender treatment; undergo a sexual-interest assessment; do not accept any paid or voluntary position involving children; do not possess child pornography or any pictures of children and have no unsupervised contact with children.

Fenn must also: Have no access to sex-related phone or TV services or Web sites; register with the state as a sex offender and submit to a search of his person, property and electronic devices, with or without a warrant, by any law-enforcement officer who asks.

In addition, said Cacheris, Fenn must submit to “having computer-monitoring software to restrict and capture his keystrokes. And, said the judge, “The defendant shall not remove or tamper with it. He shall also not possess a video or console system that would enable him access to child pornography.”

Cacheris said he’d recommend Fenn be sent to Massachusettes for incarceration in Federal Correctional Institution Devens, which has a treatment program for sex offenders.

Rhyne told Cacheris he’d file an appeal on his client’s behalf, but won’t handle it. So the judge said that, since Fenn had to forfeit all his assets, his appeal would be done by a court-appointed lawyer.

Speaking directly to Fenn, Cacheris said the former special-education teacher exhibits signs of autism and Asperger’s, himself. “You admitted you have a preference for girls, especially those ages 9-12,” he said. Cacheris also noted that more than 500 pornographic images of children were found on Fenn’s electronic devices.

“People convicted of child pornography need to be sentenced to punish them and to deter others from engaging in such behavior,” he said. “And this sentence and prison provide you with the treatment you need. You apparently were an excellent teacher and molested no children in your care. But you appear to be in denial as to your use of child pornography.”