Two police officers were shot in an East Boston neighborhood late Wednesday and the suspect, who had a tactical shotgun and body armor, is dead, authorities said.
Both officers underwent surgery at Massachusetts General Hospital and are in critical but stable condition, but they are recovering, Boston Police Commissioner William Evans said.
The officers were identified Thursday as 27-year department veteran Richard Cintolo and 12-year veteran Matthew Morris.
"They're two outstanding officers," Evans said. "We're very fortunate. We continue to pray and hope they make a full recovery."
He said Morris suffered a severed artery, and only the actions of one of his fellow officers who put his hand inside his wound to help stop the bleeding saved his life.
"He knows how close he was to death," Evans said of Morris.
Nine other officers were taken to Tufts Medical Center to treat minor injuries and emotional stress.
"Police work is a difficult job," Boston Mayor Marty Walsh added. "Often times we see what's happening around the world, and in Boston this is another example of our police officers doing the right thing - doing their job."
The suspect has been identified as Kirk Figueroa, 33, of East Boston, a bounty hunter who lived with two other roommates. According to his website, he offered security and private investigation services. He was also a sworn constable in Boston.
Officers responded to a 911 call from a home at 136 Gladstone St. just before 11 p.m. from a man who said his roommate, later identified as Figueroa, was threatening him with a knife. Two officers entered the home and were shot by Figueroa, who was then shot and killed by other officers. The second roommate was not injured in the shooting. Evans said he heard the dispute centered around the apartment's thermostat.
Figueroa was described to NBC News by a senior Boston police official as "heavily armed," and may have had as many as three firearms, including a weapon described as a "long gun/rifle."
Evans said Thursday that Figueroa had at least one tactical shotgun and a ballistic vest. He said Figueroa did not have a criminal record in Massachusetts, but did have a record in other states, including charges of arson and impersonating a police officer. He was not licensed to carry a firearm.
"No one likes to take a life," the police commissioner said. "It's the most difficult decision we make. It's unfortunate he lost his life, but he chose to use deadly force."
According to Evans, several officers entered the building after hearing gun shots and dragged out the injured officers while exchanging gunfire with Figueroa.
"All I can say is he was a dangerous individual and our officers went in there no matter what the danger," he said. "We've seen it on marathon day, and we saw it today."
Residents were asked to shelter-in-place or stay away from the area as police briefly searched for a possible second suspect. The shelter-in-place was later lifted and residents were escorted back to their homes.
Evans asked Boston to "please pray for our injured officers."
Suffolk District Attorney Dan Conley pledged Thursday that his office "will do a fair and thorough investigation."
Area residents described the chaos in the immediate moments after the shooting.
"I saw a whole bunch of guns, and the shooting kept going, and (police officers) were running," resident Eric Dicrescenzo said.
He added, "I've never been that close to a shooting in an uncontrolled area, so I was kind of freaking out."
Tiara Willdigg, whose car was parked near the scene of the shooting, said she got a phone call from a friend about the shooting.
"I was coming outside and ran out of the house and I went up there, and as I'm up there, there's mad SWAT, just ran, ran, 'Get off the street, get off the street,' heard shots popping off," she said.
Evans said it's likely no officers in the East Boston shooting were wearing body cameras because the district isn't part of the department's pilot body camera program.
Gov. Charlie Baker and Lt. Gov. Karyn Polito released a statement Thursday saying they were "shocked and saddened to learn of last night's horrific incident and their thoughts and prayers are with the police officers and their families."