Faculty and students of Villanova University were stunned yesterday by the arrest of a well-liked chemical engineering professor who was charged with selling marijuana to undercover police officers.

Authorities twice bought drugs from 48-year-old Edward R. Ritter and later found 19 bags of marijuana in his Upper Providence Township home, Montgomery County District Attorney Risa Vetri Ferman said yesterday.

Ritter was charged Thursday with possession of marijuana, possession of drug paraphernalia, and possession of marijuana with intent to deliver. Only the third count is a felony. Ritter was freed on bond.

News of the arrest caught the school by surprise. An engineering professor at Villanova who declined to be identified described Ritter as a "quiet" man who enjoyed a good reputation at the school.

"I never saw anything like this coming," the professor said.

Few faculty were at work yesterday at the Catholic university because it was Good Friday. But those who were in the engineering department talked about Ritter's arrest with shock.

Ferman said her office was investigating whether any drugs were sold by Ritter on campus.

Police say they found both marijuana and drug paraphernalia at Ritter's home.

Ritter could not be reached at his campus office yesterday. His current status at Villanova was not immediately available.