Authorities are investigating an explosion at Harvard Medical School early Saturday that they believe was intentional, reports the AP. Nobody was injured. A device exploded on the fourth floor of the Goldenson Building on Harvard's Longwood medical campus about 3am, per the Harvard Crimson. A university police officer who responded to a fire alarm spotted two people running from the building, police said.
The Boston Fire Department also responded and determined that the explosion was intentional. Police released grainy photos of two people wearing face coverings and what looked like sweatshirts. The FBI has joined the investigation as well. The extent of the damage was not clear, but the building later opened except for the fourth floor.