NIU police continue to investigate a bomb threat that shut down campus for three hours Thursday and was later determined to be a hoax.

Police from several local agencies and volunteers evacuated and closed all university buildings after a bomb threat was called in just before 6 p.m. Students, who were told through text messages to exit all campus buildings, were led mostly by volunteers through rain to the Convocation Center, which was the first building that was cleared, according to an NIU news release.

NIU Police Chief Tom Phillips confirmed a bomb threat at around 6:45 p.m., but did not provide any more details.

Not all students were aware of the threat by as late as 7 p.m. Some remained in academic and residence halls and were visible through windows.

Other people were seen walking around campus and in and out of residence halls by as late as 8 p.m. while police were conducting searches of campus buildings.

Midnight Madness resumed at 8:30 p.m., despite the threat. All other events and classes were canceled for the rest of the night.

Freshman nursing major Deja Coleman was evacuated from Neptune West at 6:30 p.m. and joined the group of students walking to the Convo.

“We don’t feel like we’re in danger,” Coleman said while waiting with a friend inside the Convo. “There’s just been a lot of stuff happening on campus. … It just makes me feel a little uneasy, I guess.”

Police concluded the threat to be a hoax, one of several that had been reported at various colleges and universities in the northern Illinois region.

“We are taking no chances with the safety of our students, faculty and staff,” said NIU President Doug Baker, according to an NIU news release. “We apologize for the inconvenience, but clearly must err on the side of caution.”

Baker sent en email to students on Friday acknowledging an excessive amount of emergency text notifications were sent out to students about the threat.

“Our goal was to make sure that every single student knew exactly what was going on at all times,” Baker wrote in the email. “Unfortunately, some texts and emails were sent multiple times while others were delayed. We realize that this created confusion and frustration. We learned from this experience and are already making changes that will improve the system.”

The last reported NIU bomb threat occurred in 2011 at Barsema Hall, according to an Oct. 31, 2011 Northern Star article. Students were evacuated at noon on Oct. 31, and classes resumed at 3 p.m. after NIU police gave an “all clear” at 2 p.m., according to the Northern Star.