The lockdown at Carroll University has been lifted and police say they have a suspect in custody after a man was reportedly seen on campus carrying a firearm.

The school, which is 30 miles from Milwaukee, sent a text alert to students after the public safety office received a report of a man with a gun near the tennis courts.

Two students reported seeing a white male in his 50s walking with a gun near the northwest corner of the campus. Carroll has about 3,500 students and is located about 30 miles from Milwaukee in the city of Waukesha.

Student Affairs administrative assistant Yolanda Medina says no one is allowed to leave the campus buildings while the report is investigated. Classes were canceled.

Fox News' Edmund DeMarche and the Associated Press contributed to this report