WALTHAM — For more than two weeks in November, a string of unprovoked, apparently random street attacks frightened residents and frustrated investigators. The assailant appeared to lie in wait for victims after dark, attacking them from behind and dashing off without stealing anything.
On Thursday, authorities said they had charged a 24-year-old man with committing the brutal assaults, which Middlesex District Attorney Marian T. Ryan described as a “reign of terror.”
“These attacks, which appear to be random, caused the community of Waltham to be in fear for several months,” Ryan said at a news conference.
Clauvens Janvier, who lives in Waltham, was arrested in December for allegedly assaulting an 18-year-old man at a parking garage on Nov. 11. He was held without bail after a dangerousness hearing while investigators linked him to the other attacks through cellphone data, video surveillance, and forensic testing, Ryan said.
Janvier is charged with attacking 11 men, including a postal worker, with blunt objects. Several men were knocked unconscious and some required hospitalization.
Among them was Emerson Antonio Aroche Paz, 42, who was attacked the night before Thanksgiving while walking down the street. He was hospitalized with severe injuries to his face and head. On Thursday, he said he was relieved that authorities had identified the man responsible for the attacks.
“And I hope that guy changes his life” while in custody, he said. “I still have pain in the back of my head every day. I don’t see too well with my left eye.”
He will soon undergo a procedure to repair damage to his nose, he said.
“All those [medical] bills, I have to pay,” Aroche Paz said.
Janvier is also charged with firing a gun at a car on Nov. 24 after having a verbal altercation with the driver at a gas station. He is scheduled to be arraigned on March 24. Janvier’s lawyer hung up on a Globe reporter Thursday and didn’t return a follow-up text message.
Janvier did not appear to be targeting specific people, or groups of people, in the attacks, Ryan said.
“It just was clearly a case of somebody being in that place where he was at the wrong time, rather than he was looking for a particular person,” she said. “There does not appear to be at this point in the investigation any particular connection either between the victims and the defendant or the victims to each other. So to that extent and given the wide range of ages and the demographics of victims they appear to be random.”
Acting Waltham police Chief Kevin O’Connell said investigators “were relentless” in their pursuit of the perpetrator.
“These attacks truly were unprecedented,” O’Connell said. O’Connell said he knew residents had remained nervous as time passed without an arrest.
“I truly understood the anxiety and the frustration of our citizens of Waltham when this case had few leads at the start and continued to go on for some time,” he said. “There was no doubt in my mind the person or persons involved would be brought to justice.”
When police searched Janvier’s car in connection with the November 11 attack, they found a machete, ammunition, and a stolen gun, prosecutors said.
The attacks began Nov. 10 near the Gardencrest apartment complex and later extended to the city’s downtown. The final attack occurred the day after Thanksgiving.
At the apartment complex, residents were relieved that the alleged attacker was in custody.
“Major league thumbs up, that’s what I say,” said Dawn O’Reilly. Maureen King said residents were reluctant to venture out at night with the suspect at large.
“You had to have food in your house before dark,” she said.
Waltham Mayor Jeannette A. McCarthy said the unexplained violence was “traumatic” for the victims and the entire city.
“I’m relieved for the entire community, because they went through hell,” McCarthy said. “My real concern is that this person not be able to do this to Waltham or any other community.”
Janvier had “caused tremendous destruction to a lot of people’s lives” and must be held accountable, she said.
City Councilor Sean Durkee, who represents the ward where some of the attacks occurred, denounced Janvier as “a terrorist.”
“I held the first neighborhood meeting after this, people were in tears,” he said.
But Aroche Paz, the man attacked the night before Thanksgiving, said he took little pleasure in Janvier’s arrest.
“He has a mother,” Aroche Paz said. “He made some kind of big mistake in his life.”
John R. Ellement of the Globe staff contributed to this report.