A jury has begun hearing testimony from a man who witnesses say was watched via webcam while kissing a Rutgers University student who committed suicide days later.

The student's roommate, Dharun Ravi, is being tried in New Jersey on privacy invasion charges and isn't accused in the death of Tyler Clementi in September 2010.

Ravi is accused of secretly watching Clementi's liaison with the man identified only as M.B. The man was Clementi's guest at least twice.

Prosecutors say Ravi used a webcam to see what they were doing once -- and tried to do it again on a second visit. Witnesses so far have said that they saw two men kissing but nothing more graphic.