A Newton activist who concealed a camera to videotape a Boston University police sergeant was convicted of violating state wiretapping laws. An associate is charged with witness intimidation.

Peter Lowney, 36, was sentenced last week to six months probation and fined $500. A Brighton District Court judge ordered him to stay away from the sergeant and remove footage from the Internet.

Lowney shot the film during a 2006 political protest. Ordered to stop recording, officers arrested Lowney for hiding the still-rolling camera in his coat.