PHOENIX -- A jury on Thursday found a school janitor who molested a Valley freshman guilty on four counts of sexual conduct with a minor, one count of sexual abuse of a minor and one count of public sexual indecency.

Roberto Lemus-Retana, 27, is an illegal immigrant who the jury said molested the 14-year-old girl after she returned to Scottsdale's Saguaro High School campus to get some books.

County Attorney Andrew Thomas told reporters he was pleased with the verdict.

"I want to praise the brave young victim who endured a trial in which the defense attorney called her a liar in open court," Thomas said. "Her willingness to come forward and testify ensures the defendant won't be able to victimize any other children or young people."

Lemus-Retana faces 52 to 86 years in prison when he is sentenced in July.

Police say Lemus-Retana was arrested less than an hour after the August 25th, 2006, incident.

Court documents show the girl -- then a freshman at Saguaro -- told Scottsdale police that Lemus-Retana raped her in a school restroom and a computer classroom when she returned to the school to retrieve some books for homework.

Court records show Lemus-Retana maintained the sex with the girl was consensual.

Scottsdale Unified School District officials said Lemus-Retana was a contract worker of A-B-M Janitorial Services, a company hired by the district to service 29 of its 34 schools.