A detective says many text messages were missing from the cellphone of a former Rutgers University student accused of using a webcam to spy on his roommate's intimate encounter with another man.

Prosecutors are trying to show that Dharun Ravi attempted to cover his tracks after his roommate, Tyler Clementi, killed himself in the days following the alleged spying.

Ravi is charged with bias intimidation, invasion of privacy and with crimes related to a cover-up.

Investigator Robert Torrisi testified Wednesday that phone records showed 86 messages exchanged with two friends that didn't turn up on Ravi's phone. Jurors heard earlier that some of those messages had to do with the alleged crimes.

(Copyright 2012 by The Associated Press.  All Rights Reserved.)