Authorities say bomb threat at Harvard was a hoax

Campus buildings were evacuated

The Cambridge Police Department’s bomb squad was on the scene Saturday.Zachary Wittman for The Boston Globe

Several buildings on Harvard University's Cambridge campus were evacuated Saturday morning after an unidentified man called police several times and said he was on the campus with an assault rifle and had placed several bombs there.

After a tense morning that saw searches by bomb-sniffing dogs and sweeps by heavily armed law enforcement officers, authorities gave the all-clear Saturday afternoon, saying the calls had been a hoax.

Cambridge Police Department spokesman Jeremy Warnick and Harvard spokesman Kevin Donovan said campus police swept the area immediately after receiving the initial call, but did not locate a gunman.

With the help of MBTA Transit Police K-9 units, the Cambridge Police Department's Explosive Ordnance Unit investigated four locations where the caller said he had placed explosives, including at the school's Science Center. They did not find a threat, Warnick said. One package described by the caller, a box wrapped in bubble wrap, was located, but an X-ray showed no explosive devices and it was removed by police.

Warnick said police are working to identify the caller and two Twitter users who sent public messages to a Globe reporter claiming responsibility for the calls.

Police detectives have turned over screen shots of the messages to the FBI's Cyber Crime division, which will investigate the matter along with the Harvard University Police Department, Warnick said.

"We've turned a lot of this information over to federal agents, and they'll work to figure out where the call and tweets came from," he said.

The account of one of the users was suspended by Twitter shortly after the messages were sent.

Warnick acknowledged that the timing of the threat, made on a holiday weekend, was somewhat unusual, as such incidents typically occur during final exams or other busy periods.

"But we have two large campuses," he said. "Regardless of time of year, there's always activity, just maybe not as concentrated."

Below are updates and images from social media:

Harvard officials have reopened buildings following a thorough search by HUPD and CPD. Campus given the all-clear. http://t.co/m8X7p9wVfx

— Harvard University (@Harvard) July 5, 2014

Harvard, Cambridge, and Boston police all parked by Harvard's science center investigating bomb threat @thecrimson pic.twitter.com/7q8N8GZWfU

— Ivan Levingston (@IvanLevingston) July 5, 2014

BREAKING: with an alleged bomb threat, Harvard has set up a perimeter around the Science Center pic.twitter.com/TFfs7PtS9i

— Tyler S. Olkowski (@OlkowskiTyler) July 5, 2014

HUPD and CPD examining bomb threat and will update community as additional information becomes available. http://t.co/wFbNB6vPJo

— Harvard University (@Harvard) July 5, 2014

HUPD in the process of examining bomb threat. Science Center and other buildings evacuated. Updates to come. http://t.co/8MXRRMMSMV

— Harvard University (@Harvard) July 5, 2014