The U.S. Justice Department has launched an investigation into allegations that up to 80 complaints of sexual assault over three years were not investigated thoroughly because of gender bias in a college town in Montana.

The investigation will look into sexual assault investigations at the University of Montana at Missoula, the Missoula Police Department and Missoula County Attorney's Office.

Assistant Attorney General Thomas Perez of the Justice Department's civil rights division said the focus of the investigation was not on the number of reported allegations but on the response.