DENVER -- A former Jefferson County music instructor and color guard coach was sentenced to 12 years in prison for sexually assaulting a teenager Thursday.

William Samuel Paxton was arrested and charged in October 2007 for having sexual contact with a 17-year-old female student who was in the marching band, said spokeswoman Pam Russell.

Paxton had been one of the instructors in the band.

On May 30, Paxton pleaded guilty to two counts of sexual assault of a child by one in a position of trust -- each a class four felony -- and one count of sexual exploitation of a child -- a class three felony.

Paxton, a father of three, began the relationship with the student by showing her personal attention and doing things like joking around and playing cards with her, Russell said.

He sent her frequent text messages throughout the day, she said, and gave her a cell phone that she used to talk to him.

The teen said that at first she liked how he treated her special. Paxton invited her over to his apartment on West Burgundy Avenue in Littleton on two occasions and sexually assaulted her, Russell said.

While Paxton was not found to be a sexually violent predator by Colorado’s official designation, District Judge Stephen Munsinger told Paxton before sentencing him Thursday that he did find him to be a sexual predator.

In addition to the prison time, Paxton will have to enroll in Intensive Supervision Sex Offender Probation for 10 years to life.