Massachusetts prosecutors scolded a judge over the sweetheart deal she handed to serial criminal Tyler Brown — who is accused of opening fire on random drivers on Monday — after he was convicted of trying to kill a cop years earlier.

Brown, 46, pleaded guilty to armed assault with intent to murder in 2021, one year after he fired 13 rounds at Boston officers, including firing a .40 Glock semi-automatic at close range at one officer’s chest.

Prosecutors recommended a 12-year prison sentence followed by five years of probation; however, Judge Janet Sanders handed out a five- to six-year sentence with three years of probation — despite the fact that Brown was already on probation for a 2014 assault conviction at the time.

The decision angered the district attorney, who apologized to the officers and blasted the attack as “brazen.”

“I am disappointed in the sentence that was imposed,” Rachael Rollins, the then-Suffolk County district attorney, said.

“Members of law enforcement put their lives at risk every day to protect us. They serve us, ​at times being unfairly criticized for ​acts committed by officers a thousand miles away felt ​and witnessed around the globe.

“Violence will not be condoned in Suffolk County. Whether that violence is committed ​by or against a domestic partner, a stranger, a loved one, ​a family member, a spouse, an acquaintance, a police officer, a suspect, anyone, we will hold the perpetrator ​of the violence accountable​ and advocate on behalf of the victim. ​​

“This sentence doesn’t do that, and I want to ​personally apologize to ​each of the​se officers and their families.  I strongly believe that the sentence we proposed — 10 to 12 years followed by five years of probation — was appropriate for the level of brazen violence committed.”

Brown pleaded guilty to eight charges in total.

The serial perp opened fire on Boston cops in May 2020 after they responded to reports of a gunman threatening people.

Neither officer was injured despite Brown aiming at an officer’s chest from close range.

A cop caught up in the attack said in a victim statement, “I am a firm believer that when Mr. Tyler Brown gets out, he will hurt, or worse, kill someone,” NBC10 reported.

Brown had only been out of prison since January, William Gross, the Boston police commissioner, told reporters following Monday’s erratic rampage in Cambridge. 

Brown allegedly fired between 50 and 60 shots at cars on Memorial Drive, leaving two men critically injured.

Driver Brandon Mansolf told WBZ-TV that he stopped his car and crouched inside it when bullets suddenly struck his radiator and his co-worker’s headlight in front of him.

“Got out, walked up to the car in front of me to my co-worker to see what was going on. Saw the dude in the street lifting [the gun] up at me,” the witness recalled.

“I dipped back into my car and ducked behind my dashboard. My buddy got out; he ran for it. State trooper pulled up directly on the side of me, got out, got behind his car right in front of my driver’s side mirror, got in the gunfight with him.”

Mansolf said there was “blood everywhere” with shell casings strewn across the road, while witness Joseph Minino-Rodriguez compared the barrage to a “video game.”

“He’s like mad. He’s frustrated. I don’t know what happened. I don’t know what’s going on with him,” he said.

Another rattled witness, Todd Czubek. told CBS Brown was “shooting randomly, up in the air, spraying the area.”

“He’s shooting all over the place, goes into the road, all the cars are stopped both ways and he’s just shooting,” he added.

“People started to get out of their vehicles and run, including me.”

Brown was hit several times after being confronted by a Massachusetts state cop and a Marine who was licensed to carry a firearm.

He was hospitalized and is awaiting arraignment.

Marian Ryan, the Middlesex County district attorney, said he’s expected to be charged with two counts of armed assault with intent to murder.