Two Massachusetts men arrested in connection with an explosion Saturday at Harvard University are accused of detonating a firework inside a laboratory locker in a medical building, federal authorities said Tuesday.
Logan David Patterson, 18, of Bourne, and Dominick Frank Cardoza, 20, of Plymouth, were charged with conspiracy to damage by means of fire or an explosive. If convicted, they could face up to five years in prison, three years of supervised release and fines of up to $250,000.
Cardoza's lawyer didn't immediately respond to NBC News' request for comment. It's not clear whether Patterson has an attorney.
Around 2:33 a.m. Saturday, Patterson and Cardoza were seen on security video wearing face coverings, walking near the school’s medical building and lighting what appeared to be a Roman candle firework, Leah Foley, the U.S. attorney for the District of Massachusetts, said at a news conference.
About 10 minutes later, they were seen climbing scaffolding and accessing a building’s roof before fleeing, Foley said.
The explosion happened on the fourth floor of the Goldenson Building, part of the school’s medical campus in Boston. The firework was detonated inside a laboratory locker, Foley said.
The building was empty, and there were no reports of injuries.
"This explosive device had the potential to cause significant injury to anyone nearby. But only by sheer luck and because of a rapid response by first responders, no lives were lost, no one was injured, and property damage was limited," said Ted Docks, special agent in charge of the FBI in Boston.
An initial assessment by the Boston Fire Department found that the explosion "appeared to be intentional."
A tip from the public led law enforcement officers to Patterson and Cardoza after Harvard police released images of them from security video. University, local and state police assisted in the arrests.
In a message to the school community, Harvard police said there was no further "threat to public safety." The school directed additional questions to the U.S. attorney's office.
A motive is still being investigated. Docks alleged that Cardoza tried to throw away the pants he was wearing on the day of the explosion and that both men "boasted" about it to their friends.
