Twitter exploded Saturday morning after a gunman wearing body armor was reportedly spotted on the MIT campus, which is terrifying. Except after the smoke cleared and no gunman was found, it appears the whole thing was a hoax.

So, from what we can gather, Cambridge police received a report around 7:30 a.m. Saturday morning of a gunman on MIT's campus and dispatched "all available" units. The school went into lockdown. The school's website automatically redirected to this emergency warning page:

This morning information was received from Cambridge Police that there was a person with a long rifle and body armor in the Main Group Building of MIT.  Multiple law enforcement agencies have responded. Stay indoors and shelter in place and report suspicious activity to the campus police dispatch at 617 253 1212 or dial 100 from a campus phone.  More updates to follow.

Emails were sent to staff members warning them of the possible threat. The warning was bolstered by a previous report of a gunman on Massachusetts Avenue, about two miles from the building on campus where the gunman was reportedly seen. People were scarred, and rightfully so. But some observers noted there was very little scanner activity from Cambridge police after everyone started paying attention, and the first sign it was a hoax appeared. Shortly after, the police confirmed their search of the school's Main Group Building didn't find anyone with a gun. A little while later, they confirmed the scene was clear and the reports of the gunman were totally unfounded. The whole thing was over and the scene was being cleared by 10 a.m.

So, where did they come from originally? It's unclear right now. MIT Tech staff reporter John Hawkinson reports the first alert sent to Cambridge police was allegedly received in an email Saturday morning. Moreover, the IP address the email was sent from was based in New York City, which doesn't make any sense. How could someone in New York City see a gunman on MIT's campus?

Regardless of whether or not it was a hoax, Cambridge police were still in the right to respond as they did. But it raises the question of who, exactly, would find this funny? Who would want to scare little old grandmothers? We've put in a request for comment from the school and we'll report if we hear anything back. Despite the initial scare being over, this is still a developing story and we'll update this space once we know more. 

Update 1:20 p.m.: Cambridge police held a press conference Saturday confirming they did receive an electronic tip, but did not confirm it was in an email. They are currently investigating the source of the false tip and that person will face charges. Approximately 30 officers responded to the call that shut down MIT for about three hours. "Report came in as [a] possible barricaded armed suspect, but it turned out to be a hoax," a police official told The Boston Globe