BATON ROUGE (AP) — The thousands of students who live on the Louisiana State University campus will be able to return to their dormitories after bomb-sniffing dogs and police methodically swept residential halls Monday following a threat that sparked a campus-wide evacuation.

LSU spokesman Herb Vincent said officials hoped to reopen the Baton Rouge campus by Monday night, but they weren’t certain if a building-by-building sweep will be complete before today.

“Residential Life buildings have now been deemed ready to return to normal operations. That notification is going out now to the campus community,” Vincent said.

Evangeline Hall, a residential building on campus, was reopened first and officials began siphoning some of the 6,000 on-campus residents into the building as the investigation continued, Vincent said. He said residential halls were searched first and buses to and from the campus have been running normally.

Thousands of students, professors and workers were told to leave campus after a threat was phoned into 911 about 10:32 a.m., university spokeswoman Kristine Calongne said.

But the threat did not indicate a specific part of campus, so police and bomb-sniffing dogs have been meticulously sweeping each of the 250 buildings on campus.

LSU Police Capt. Corey Lalonde said no explosives have been found thus far.

By mid-afternoon, the LSU campus was largely deserted and roads were closed, though some people and cars were still moving around. Police officers with dogs combed through buildings, including the computer services center.

State police bomb technicians were on the scene, said Louisiana State Police Capt. Doug Cain. He said authorities were talking to their counterparts in Texas, North Dakota and Ohio, where similar threats were received Friday, but officials say they’re not sure if the phone call made Monday was connected to those threats. Police found no explosives on those campuses.

“It’s kind of been an epidemic. This has been the fourth in a week. But it’s better to be safe than sorry,” said Joseph Vera, a communications disorders graduate student.

Vera and a fellow graduate student were working in a language clinic with seven children near the edge of campus when they received the text message about the bomb threat. The pair walked the children across the street to an off-campus restaurant and they called the children’s parents.

The university sent a follow-up message to students at 1:36 p.m. telling them not to return.

Col. Mike Edmonson, Louisiana State Police superintendent, said despite some initial traffic congestion, the campus was evacuated in under an hour.

“Our goal is for the campus life and community at LSU to return to normal, that’s our goal here,” he said.

The university put out a statement on its website announcing the evacuation an hour after the phone call was received, then distributed the information through text messages, emails and social media.

“A bomb threat has been reported on the LSU campus,” the statement said. “Please evacuate as calmly and quickly as possible.”

There are 30,000 students, professors and university employees located on the Baton Rouge campus, but it was not clear how many were there at the time of the threat.

“Monday … is a very big class day, so I think the majority of that group was probably on campus at the time,” Calongne said.

Catherine Lacoste, an 18-year-old freshman and architecture major, said she received notification by text message while working in a studio on a project. She double-checked the information and then evacuated.

“I’m going to go home, take a nap and hopefully campus will be open again when I wake up,” Lacoste said.

Kayla Johnson, 18, an English major, heard about the evacuation from a student who received the text message.

“I was in the middle of class and one of the guys in the back of the room raised his hand and said, ‘The reason it’s so loud outside is because there’s been a bomb threat and we have to leave,”’ Johnson said.

Students largely seemed to take the evacuation in stride.

“Nobody seems too worried about it,” said Shelby Miller, 18, a biology major who was doing homework and eating Chinese food at the student union when she got word of the evacuation.

Miller headed to a nearby coffee shop right off campus to finish her homework.

Calongne said she doesn’t know of any other time the entire flagship university campus was evacuated.

“I’ve been at LSU since 1990 — if you count my student years — and I don’t ever recall us having an evacuation of the whole campus,” she said.