The Health Services building was given an all clear at 4:15 p.m. after a bomb threat was found at 2 p.m. Thursday.

About 2 p.m., a note with a bomb threat was found in a stairway at the Health Services building, said Melanie Magara, assistant vice president for Public Affairs. The note mentioned a specific time that an explosive would supposedly detonate, she said.

“This issue of specificity raises the ante of what level of response is called for,” Magara said.

The stairway was traveled enough to be of recent origin, she said, and an estimated 75 people were evacuated from the building and sent to the Wirtz Hall lobby.

Police did two sweeps of the Health Services building with K-9 units and found nothing.

The evacuated departments in the building include the Speech and Hearing Clinic, the telecommunications offices and the Public Safety offices.

“We are handling this the way we would handle a bomb threat,” NIU President John Peters said. “We are taking it seriously.”

Magara did not know who reported the note and did not know additional details of the note.

Classes were not canceled, and all night operation continued as scheduled, according to an NIU press release.

“The university posted news of the threat on its home page and notified the campus community via e-mail and telephone messages,” according to the press release.

Magara said while the Feb. 14 shootings raised concerns, the response was not handled differently than normal.

“We cannot help be more prepared for more public interest,” she said. “We didn’t respond all that different.”

Students expressed mixed opinions after receiving word of Thursday’s threat.

“When I first saw this on the NIU Web site, my heart just jumped,” senior sociology major Chelsea Edwards said. “I was in the same lab when the shootings happened.”

Others, though, were more indifferent.

“It didn’t really phase me,” senior physics major Eric Johnson said. Johnson compared his reaction to the December threat, which he did not take seriously. “I feel like they wouldn’t give us a warning before they do it; it’s more of a sick joke or something like that.”

NIU Police are continuing to investigate the matter, according to the press release.

Alan Edrinn, Patrick Yeagle, James Tschirhart, Brett Michelson and Lee Blank contributed to this report.