The University of Montana "appears to have a gap in reporting sexual assaults," according to a preliminary report released Tuesday by an investigator hired last month by the school.

"There is evidence of non-consensual sex that is not being reported in the university system," according to the investigator, former Montana Supreme Court Justice Diane Barz. She added that her report - originally to have been completed within two weeks - "as a practical matter" will take more than two months.

The university commissioned Barz's probe in mid-December after allegations surfaced about two female students, possibly drugged, being gang-raped by male students. UM Vice President Jim Foley said at the time that the investigation would review only incidents on campus, which includes Greek housing.

But Barz's investigation now includes a third assault, possibly off campus. "...There is evidence that there has been a sexual assault that has not been appropriately reported and investigated," Barz wrote in her preliminary report that went to UM President Royce Engstrom on Saturday and was posted Tuesday on the school's website.

Foley said Tuesday that "there are three allegations that I'm aware of as of this morning." A statement he released Tuesday said those incidents may have occurred on or off campus.