A parent volunteer at a Greeley charter school has been arrested in connection with the sexual assault of a teenager at her home, police said Thursday.Lynne Freeman, 38, was arrested Wednesday on investigation of sexual assault on a child, said Greeley police spokeswoman Sgt. Susan West.Freeman is a parent volunteer at University Schools, a charter school in Greeley School District 6.However, the teenage boy is not a student in the classes where Freeman volunteers, West said.The sexual assault occurred on April 10, but it was not reported to police until June 10, when the boy told his parents he'd been molested, West said. The parents then contacted police.The teen told police he was visiting Freeman's home when the assault occurred, West said.The boy said Freeman took him upstairs into a bedroom closet, locked the door behind them and began kissing him, West said. The boy said that Freeman then removed his pants and performed a sexual act on him.She then told him to not tell anyone what happened and to go back downstairs, West said.Police earlier described Freeman as a "teacher's aid" in a news release. The school informed the police department of her status.Police are continuing to investigate, and ask anyone with information to call Sgt. Adam Turk at 970-351-5381 or Investigator Greg Tharp at 970-350-9533.