A former Montgomery County dance instructor was sentenced Wednesday to nine to 23 months in jail for having sex with a female student over the course of two years.

Frank Laurenzi met his victim when she was 10, prosecutors said, and began giving her private ballroom dance lessons when she was 14. By the time she was 15, he had sex with the girl during their lessons and videotaped some of their sexual encounters.

He pleaded guilty in November to statutory sexual assault and sexual abuse of children.

"I crossed a line that I shouldn't have crossed," Laurenzi, 29, of Norristown, told Montgomery County Judge Garrett Page at his sentencing hearing Wednesday.

Assistant District Attorney Kathleen Colgan said Laurenzi knew better than to assault a young girl, especially because he graduated near the top of his class from the police academy but chose to pursue a career in dance instead.

"He is smooth. He is cunning, and he is articulate," Colgan said. "And I agree that he is sorry, but I believe he is sorry that he got caught."

Laurenzi taught at LeRoux Dance Studio in Royersford and later opened his own studio in Conshohocken.

The victim, now 18, addressed Laurenzi in court Wednesday. She said she had been afraid to tell anyone about the inappropriate relationship and has struggled to move on since coming forward.

"Tomorrow, I'm graduating high school," she said, crying on the witness stand. "If you asked me if I was going to graduate high school a year ago or two years ago, I would have said no."

Laurenzi will report to jail in July. He will be eligible for work release after five months. He also received a sentence of five years probation.

- Laura McCrystal