Fortunately, this was just a hoax. Disturbingly, it comes only half a year after a Harvard sophomore sent anonymous emails to the university claiming there were bombs across campus so he could avoid taking a final exam.

Dan Adams of the Boston Glob has the story on this most recent hoax:

Authorities say bomb threat at Harvard was a hoax

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.