A crazed ex-fireman allegedly launched into a violent rampage after his ex-girlfriend dumped him — and was “ready for war” when he drove eight hours intending to kill her family in New Jersey, according to prosecutors.

Brian John Lanzim, 37, was armed with two guns and a bulletproof vest when he headed from Bangor, Maine to South Toms River, after the mother of his two kids broke up with him and filed a temporary restraining order against him, authorities said.

He allegedly wanted to kill off his ex’s family to get custody of his kids, according to prosecutors — but his lawyer claimed he was actually trying to die “by suicide by cops,” according to Patch.com.

“He absolutely f–ked up. He f–ked up big time,” Lanzim’s good friend, who asked not to be named, told The Post.

The former Toms River firefighter allegedly sent terrifying threats to his ex on April 29 — letting her know he was armed, dangerous and on his way over.

“If your father is there I’m going to take him out” and beat him “pulseless,” he allegedly told the woman, as Ocean County Judge Pamela M. Snyder read aloud in court Friday morning.

“You don’t know crazy yet,” he also allegedly warned his ex during a chilling FaceTime call, NJ.com reported.

The people inside the home he was targeting fled the scene and alerted police long before he arrived, authorities said.

When Lanzim showed up after 9:40 p.m., he allegedly floored his Toyota 4Runner over the lawn in a sick attempt to run over the waiting cops, according to the Ocean County Prosecutor’s Office.

The officers then dove behind a fence and watched as gun-wielding Lanzim pounded on a locked door of the vacant house, prosecutors said.

“Brian, put it down!” one of the Toms River police officers demanded, according to NJ.com.

“No!” Lanzim resisted, per the body camera footage.

Police then fired at Lanzim, striking him in his hand and pelvis nonfatality. He was taken to Jersey Shore University Medical Center in Neptune before being moved to Ocean County Jail.

Investigators found a loaded rifle and a large amount of ammunition magazines in his car, prosecutors said. He reportedly had a handgun on him when he was shot.

He’s been charged with three counts of attempted murder, two counts of weapons possession for an unlawful purpose, unlawful use of body armor, burglary, terroristic threats and 22 counts of possession of a large capacity of ammunition magazines.

“He was ready for war,” Assistant Prosecutor Mara Brater said at his detention hearing — warning that if the victims hadn’t fled the home and called police before he arrived, he would have committed even more heinous crimes.

Brater went on to claim that Lanzim’s sinister plan was to kill or harm his ex’s family so he could get full custody.

But Lanzim’s lawyer Marissa Koerner brazenly argued his alleged violent outburst was caused by a mental breakdown triggered by the breakup. He also has bipolar disorder and was in treatment for it, she said.

“‘I f–king lost her, man. Tell her and the boys I love them,’” Lanzim allegedly said, per an affidavit Koerner read aloud.

“He loves his family,” she argued.

By wearing a bulletproof vest, Lanzim was trying to “force a kill shot to the head” during his heated exchange with police, the lawyer told the court.

But Brater shot down these claims — alleging that his targets begged him not to go through with his horrifying plot.

He also allegedly has a track-record of violence — including an instance where he pulled a gun on his ex and said, “If I can’t have you, no one can.”

The judge ordered that Lanzim will remain in custody awaiting trial, according to court records. He’s due back in court on May 18.

Lanzim was a fireman and EMT in Ocean County for about 18 years before heading to Bangor in September 2025 for a new job.

“He couldn’t find employment in New Jersey,” his close friend claimed. “I’m not sure what was going on, I guess things fell apart up there [in Bangor].”

Lanzim’s friend spoke with him just days before the incident.

“I had messaged him and asked him if he was okay. He said no. I said, ‘does it have to do with the kid’s mother?’ And he said yes,” the man said.

“I asked, ‘you need me to call you?’ and he was like, ‘I’m okay, I’m just at Applebee’s trying to find the bottom of the glass right now.’”

The next time he heard Lanzim’s name was when he made headlines for the alleged horrors.

“I hope that kid [Lanzim] gets the help he needs,” the friend said. “Brian sometimes doesn’t act like an adult, and where he is now and where he’s going to be going, he has no choice but to. I would say man up.”

Lanzim’s attorney did not respond to a request for comment.