GREELEY, Colo. -- A former professor accused of secretly videotaping more than a dozen young men in his bathroom at his home was sentenced Wednesday to four years in prison.

The former University of Northern Colorado theater professor, 63-year-old Raymond "Vance" Fulkerson, also will have to register as a sex offender.

Fulkerson pleaded guilty in January to one felony count of sexual exploitation of a child.

He is accused of secretly videotaping at least 13 male students as they showered and used the bathroom. One of the students found the camera hidden inside a digital clock in Fulkerson's bathroom in July.

Police said Fulkerson told them he initially placed the camera in the bathroom to keep track of his aging parents.

Fulkerson had faced from probation up to 12 years in prison.

The professor had been at UNC since 1989. He has directed several productions including "Chess," "The Rocky Horror Picture Show," and "Hairspray."