The New Jersey tech boss convicted of killing his brother and his brother’s family in their upscale Colts Neck mansion in 2018 was sentenced to die in prison Tuesday — as the judge slammed him as a “heartless, brutal killer.”

Monmouth County Judge Marc Lemieux sentenced Paul Caneiro, 59, to the mandatory penalty of four life sentences without the possibility of parole.

“In this case, there was an avalanche of evidence pointing to the defendant being a callous, heartless, brutal killer,” Lemieux said at the Tuesday sentencing.

“This was an annihilation of an entire family, a mass murder carried out by a person who should have protected them the most … because the defendant constructed lies that were collapsing down around him,” the judge added.

“He was and continues to be a manipulative, cold-blooded killer.”

Caneiro was convicted by a jury in February of shooting his business partner brother, Keith Caneiro, 50, outside the sibling’s mansion before going inside and shooting and stabbing Keith’s 45-year-old wife, Jennifer, on Nov. 20, 2018.

Paul then stabbed his niece and nephew, Sophia, 8, and Jesse, 11, before setting the home on fire and returning to his own Ocean Township house, lighting a blaze there too to make it appear as though he was also being targeted. Paul’s wife and two daughters were unscathed.

Jennifer’s mother, Bette Karidis, told the judge ahead of sentencing that “a thousand years would not be enough” of a punishment for Paul, whom she slammed as a “monster” and “pure evil.”

“In an act of pure evil, he took the life of four innocent people,” Karidis said. “His own flesh and blood out of greed and selfishness. He disgusts us.

“He stole the source of joy and happiness in our lives and replaced it with bottomless sadness, sorrow and grief.”

Jennifer’s sister, Bonnie Karidis, called for the harshest sentence possible, saying Paul “must be removed from society.”

“The sheer malice and betrayal is unbearable,” Bonnie said. “They were executed and tortured by someone who was family … they welcomed him into their space and he took their lives for material wealth.

“The satin in this room stole decades of laughter, holidays, graduations and weddings from all of us for temporary material wealth,” Bonnie said.

Paul looked on somberly, wearing yellow jail clothes. He did not speak in court but his lawyer Monika Mastellone said he “maintains his innocence.”

“The amount of loss and devastation is truly immeasurable,” Mastellone said. “There is nothing I can say to mitigate that tragedy.”

He stood — his face stoic, and unchanging — with his hands cuffed in front of him and his wrists linked to a leather belt around his waist as the judge read his lengthy decision. 

“His address will forever be the Department of Corrections,” Lemieux concluded.

“You are no longer Paul Caneiro … you are a quadruple murderer, who slaughtered innocent children. That is your identity,” the judge said, adding he will be “confined to a 4-foot by 7-foot cell until your final breath.”

Lemieux emphasized the horror of Paul’s acts, in particular the ones he unleashed on his young niece and nephew, as he “hunted them with a knife” in their own home. 

The kids tried to fight off their 230-pound uncle but didn’t stand a chance — Sophia weighing a slight 45 pounds and Jesse weighing 90 pounds, the judge said.

And after visciously repeatedly stabbing them, the kids were found with smoke inhalation injuries during their autopsy, indicating they were still alive and breathing as the slow-burning fire consumed the house, the judge said.

A woman could be hearing saying, “Oh Jesus” as Lemieux described how Paul stabbed Sophia in the nasal cavity and chest causing her lung to collapse.

Lemieux also repeatedly noted that Paul showed no remorse.

Paul was driven to the grisly slayings in a bid to silence Keith after the younger brother confronted Paul about stealing $80,000 from Keith’s trust meant to fund his life insurance policy, prosecutors alleged at trial.

Paul — who owned a tech company and an extermination company with Keith — was struggling financially, paying for four luxury cars and bankrolling trips with his gal pal Yisel Restrepo, prosecutors claimed.

Meanwhile, Paul’s lawyer, Monika Mastellone, argued at trial that a third Caneiro brother, Corey, may have actually been responsible for the murders and framed Paul.

Paul would forfeit his share of Keith’s $3 million trust if convicted of murder, leaving Corey as the sole inheritor, Mastellone argued.

And Paul loved Keith and his family too much to ever be capable of murdering them, the defense lawyer argued.

Paul cried when Mastellone described how close he was to the victims.

Paul also wasn’t actually overextended like prosecutors contended, since he was collecting $200,000 in disability payments and the extermination company was potentially going to be sold for hundreds of thousands of dollars, Mastellone argued.

The jury found Paul guilty of all charges, including murder, aggravated arson, weapons possession and hindering apprehension.