People for the Ethical Treatment of Animals is suing the University of Massachusetts to force it to release documentation of experiments on monkeys.
PETA says UMass-Amherst has photos and videos produced as part of a 17-year study examining why and how monkeys confined to lab cages engage in self-mutilation.
The animal rights group says the lawsuit was prompted by the university refusing to comply with its open-records request.
It had appealed to the state after UMass claimed the material was exempt from the public records law, and the state sided with PETA last year.
College officials say they will not comment because of the pending litigation.