Authorities have launched a federal investigation after an intentional explosion shook the Harvard Medical School campus early Saturday morning. The blast occurred inside the Goldenson Building, home to the university’s molecular biology and genetics laboratories, prompting an immediate response from local and federal law enforcement agencies.
According to the Harvard University Police Department (HUPD), the explosion took place around 2:48 a.m. and caused structural damage but no reported injuries.
HUPD spokesperson Steven G. Catalano said an officer on patrol witnessed two individuals fleeing the scene moments before the explosion.
“The Boston Fire Department Arson Unit has determined the explosion to be intentional,” Catalano said. “We are working closely with local, state, and federal authorities to identify the individuals involved.”
Police release photos of two individuals they are looking for in connection with intentional explosion overnight in a building at Harvard Medical School
(Photos from police press release)
More details on the incident here: https://t.co/hPwl6syUJv pic.twitter.com/JDBPQvF1W2— Steve Lookner (@lookner) November 1, 2025
Surveillance Images Released of Masked Suspects
By Saturday afternoon, investigators released surveillance photos showing two masked men wearing dark hooded sweatshirts and ski masks walking near the site of the explosion.
Both men are now considered persons of interest in what police are calling the “Harvard Bombing – CAS Incident”, short for Chemical and Academic Sciences.
Authorities are urging anyone with information to contact the Harvard Detective Bureau at 617-495-1796. The Boston Police Department (BPD) and FBI Boston Field Office, with assistance from the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), are leading the investigation.
BPD confirmed that the Goldenson Building was swept for additional explosive devices, but none were found.
Federal Agents Examine Chemical Residue
FBI spokesperson Kristen M. Setera called the inquiry a “complex, coordinated investigation.” Forensic experts are analyzing chemical residue samples to identify the device’s composition and source materials.
“At this stage, we can confirm the incident was deliberate,” Setera said. “Our teams are working with campus security to establish a timeline and identify the suspects seen fleeing the scene.”
No group has claimed responsibility for the explosion. Investigators are exploring potential motives, including academic sabotage or politically motivated vandalism.
Boston Fire officials described the blast as “contained but concerning”, noting that the explosive device appeared to be locally assembled, possibly from materials accessible within research labs.
Harvard Tightens Campus Security
Following the explosion, Harvard University increased security across the Longwood Medical Area, which also includes Brigham and Women’s Hospital and the Dana-Farber Cancer Institute.
In a notice to staff and students, the university urged caution and vigilance.
“There is no immediate threat to the campus community,” Harvard’s statement read, “but patrols have been increased out of caution.”
The Goldenson Building remains closed as FBI forensic teams continue examining the site. Investigators are reviewing additional surveillance footage from surrounding buildings and streets to trace the suspects’ escape route.
“This investigation remains very active,” Harvard Police said. “We are pursuing all leads.”
