BLOOMINGTON, Ind. — Indiana University says gunshots believed to have been fired by suspects in an off-campus robbery led to an alert of an active shooter.

The Bloomington campus sent out an alert at around 1:30 a.m. Sunday warning people to take shelter or avoid the area entirely. The university tweeted that police were responding to a report of an active shooter on campus.

Indiana University says the shots were fired near a parking garage and the suspects fled on foot. The school says there are no known injuries, and it lifted the shelter-in-place warning about an hour and a half after it was first issued.

Police are investigating.