Radnor Township police have charged an already-jailed Montgomery County man, who has a history of stalking women, in alleged additional stalking incidents at Villanova University.

"This guy is sick," said William Colarulo, the Radnor police superintendent.

Korwell Chan, 39, of Dresher, who was being held in the Montgomery County jail on a probation violation, was charged with stalking, harassment, and trespass for incidents in the fall, and trespass for an April 22 episode, police said.

"This individual has a chronic problem of targeting unsuspecting and helpless females by stalking them and breaking into their homes or taking improper pictures of them," Colarulo said.

On April 22, Colarulo said, the Villanova University Public Safety office contacted Radnor police after Chan entered the Falvey Memorial Library without permission. In the fall, Chan allegedly stalked a female student at the library on at least 10 occasions, according to Colarulo.

The 21-year-old student reported the fall incidents to campus security, but at the time did not want to pursue further action, said Dave Tedjeske, the university's director of public safety. She has since filed a police report, he said.

Colarulo said that he was concerned about Chan's escalating improper behavior.

Police said Chan, who lives with his parents, attended West Chester University and works at a car wash.

In December 2012, Chan pleaded guilty to invasion of privacy and related offenses for a May 2012 incident in which he followed a woman at the King of Prussia mall and placed a camera he had hidden in a bag under her skirt to take images showing her underwear.

In March 2013, Chan pleaded guilty to burglary, stalking, and theft after he broke into the home of a woman he had befriended and stole her underwear.