Seton Hall University reopened Thursday night after a false bomb threat forced an evacuation, reported the Newark Star-Ledger.

About 100 people were on the South Orange, N.J campus when a threat that claimed bombs were placed in every building was made at around 3:30 p.m. According to Essex County Sheriff Armanda Fontuora, the threat was posted on Facebook.

Officials at Seton Hall said evacuation began at about 3:36 p.m., but only two of the campus' 15 buildings were being occupied at the time. Summer classes had just begun.

"We have just been notified by the South Orange Police of an online posting threatening our campus," said Dan Kalmanson, the school's associate vice president for public relations and marketing.

Fontoura said the campus was cleared of all threats at 5:30 p.m. and just before six that evening, the campus was reopened.

Police called the threat "unverified" and "non-specific" in an emergency alert sent out to the whole campus. Despite such a heightened alarm and serious threat, Seton Hall senior Paul Murphy said evacuation went smoothly.

"No one really knew what was going on," said Murphy, who was walking to class when the alert came in. He added that no one panicked and those who were on campus acted orderly and calm.

Despite the clearance of the campus and no threat being found, Fontoura did not discount the legitimacy of the threat.

"Hopefully, there is nothing to it," he said.

Dozens of emergency vehicles occupied the main entrance to the university as responders searched through every building before declaring the campus safe.

"The Essex County Bomb Squad and other local law enforcement agencies conducted a thorough search of each of the buildings on campus and found no evidence of explosive devices," Kalmanson said in a statement Thursday night. "Only residence students and essential University personnel are being allowed back on campus at this time. All classes and campus operations will resume as normal beginning Friday."

Kalmanson also said the school is currently working with the police to investigate the source of the threat.

"The University takes threats of this nature seriously and is working closely with police officials to investigate the matter," he said.