Harvard’s police department said that on Saturday, just before 3 a.m., one of its officers responded to a fire alarm at the Goldenson Building at 220 Longwood Ave., and saw two people fleeing.
Inside, police said, the officer found evidence of an explosion in an area on the building’s fourth floor, which houses research labs for the school’s neurobiology department. The Boston Fire Department’s arson unit said it appeared to have been deliberate. Boston Police swept the building and didn’t find any other explosives.
A Boston FBI spokesperson said an investigation was “active” but declined to comment further.
Harvard released images of two suspects and asked for the public’s help in identifying them.
Harvard’s Goldenson building was open Sunday, with the exception of its fourth floor, but medical school officials told staff they should not come to the campus over the weekend if they had not already planned to do so.
The medical school’s quad also remained open to the public. It was largely empty Sunday morning, as a few students strolled by with coffees, and a handful of tourists took pictures of the marble façades.
One person stopped to pose for a photo holding up a medal from the Cambridge Half Marathon. Outside the Tosteson Medical Education Center across the quad, a young man sat at a table studying.
Students in the area declined to be named in interviews, but said their work seemed to be continuing largely as usual, in spite of what had taken place here just the day before.
A small police presence was in the area but there was otherwise little sign of a crime scene in Longwood, a hub for medical care and research. Business was continuing as usual at neighboring institutions, including Boston Children’s Hospital, where a spokesperson said patient care had not been impacted.
Scaffolding clinging to the side of the Goldenson building had been installed weeks earlier along one corner of the building as part of ongoing facade restoration work, a Harvard spokesperson said. Translucent tarp wrapped around it flapped in the chilly breeze.
While authorities said they believed the explosion was set off intentionally, it was not yet clear what might have motivated whoever was responsible. No evidence had been released publicly that the building had been targeted for ideological reasons.
It was also not yet clear how the suspects might have entered the property, which students said typically requires a key card to access.
Harvard has been more on edge than usual in recent years about potential attackers given its high profile and tension with the Trump administration.
Earlier this year, the university said it would pay security expenses for Harvard Hillel, a Jewish campus organization, amid fears of antisemitic violence.
Harvard has also been targeted by bomb threats in the recent past. A New Hampshire man was sentenced in 2024 to three years’ probation after he was found to have brought a hoax device to Harvard’s Science Center Plaza in Cambridge in 2023. Investigators later found he’d unwittingly been recruited to do so after answering a Craigslist ad, in a scheme allegedly orchestrated by someone else, who later called the university demanding a large amount of cryptocurrency.
