Christopher David Powell, 22, taken for a prior arrest on Feb. 9, 2007

A 22-year-old contract cleaning employee for the University of Colorado's Boulder campus was ticketed for unlawful sexual contact after one of his co-workers told police that he thrust his pelvis into her butt several times when she bent over.

Christopher David Powell, of Longmont, and a 32-year-old co-worker, who police aren't identifying, were cleaning Farrand Hall about noon Monday and had to go into a closet to hook up a hose, said CU police Cmdr. Tim McGraw. While they were in the closet, McGraw said, the woman said Powell "bumped his pelvis against her back side a couple times and grabbed her buttocks."

"She contends that he bumped up against her on three or four occasions over her objections and then grabbed her butt as she was leaving the closet," McGraw said.

Powell denied any wrongdoing to police, he said.

"(Powell) said the door closed behind him, and there may have been some incidental contact, but it was not as she contended," according to McGraw.