An illegal Guatemalan migrant allegedly behind a twisted year-long arson spree on Long Island walked free under the state’s bail reform laws – but was quickly handed over to ICE in a coordinated effort to keep him behind bars, according to police and officials.

Elder Lopez Avalos, 27, was scooped up by federal immigration agents Tuesday after a judge was forced to cut him loose on non-bail-eligible offenses following his arrest over sparking a string of destructive car fires in Freeport, including a late-night blaze at a municipal parking lot on Sunday.

ICE issued a detainer after his Sunday arrest, and under an agreement with the agency, authorities picked up the accused firebug Tuesday morning and turned him over to the feds.

Nassau County District Attorney Anne Donnelly blasted New York’s bail reform laws during an afternoon press conference.

“The fact that we even have to do this and have to jump through that extra hoop just goes to show you that these bail reform laws are not working,” Donnelly told reporters.

“You’re handcuffing law enforcement.”

Nassau Police Commissioner Patrick Ryder, who supports toppling that state’s controversial bail policies, said his department works with all federal partners and will not hesitate to send criminal illegal immigrants into federal custody.

“What we do in Nassau County is if you get arrested, we run your name in the New York State database, and it tells me if there is a detainer, or a judicial hold on you,” Ryder said.

“I will turn you over to ICE. That’s my obligation, and my responsibility to do so. But at the end of the day, it’s real simple – don’t get arrested, and you’re not getting turned over by Nassau County.”

Avalos, a Baldwin resident, was arrested Sunday after cops responded to Municipal Parking Field 1 on Smith Street around 1:30 a.m. and found four parked cars engulfed in flames, police said.

The alleged arsonist, found near the scene, was later tied to earlier car fires on May 2, June 18, 2025, and June 29, 2025. Avalos is also accused of setting brush and dumpster fires along Nassau’s south shore, according to authorities.

“This is dangerous stuff. We’re talking about setting a car on fire with 20 or 30 gallons of gasoline – it’s like a bomb,” Nassau County Executive Bruce Blakeman said.

“This could have been a real tragedy. I’m talking about the loss of human life, innocent people. These people that engage in these multiple arsons, they’re sick people, and they’re out there in our community – we gotta stop them and make sure that we use every tool in the box.”

Authorities said Avalos would rip up a T-shirt, stuff the torn pieces into gas caps, and ignite them, creating “improvised incendiary devices,” with alleged property damage exceeding $1 million.

The suspected fire starter was hit with 11 counts of arson, one count of reckless endangerment, and one count of criminal mischief.

But because arson is a non-bail-eligible offense under the state’s bail reform laws, a judge had no choice but to release him back into the community following his arraignment.

“If you put volunteer firefighters, and the residents of Nassau County in jeopardy – that alone should keep you behind bars,” Nassau County Chief Fire Marshal Mike Uttaro stressed.

Authorities said Avalos had no ID and no fingerprints on file after being arrested – and allegedly admitted to entering the US illegally through the Texas border from Guatemala.

He was then driven to Westchester County before settling in Freeport with his brother.

Police took Avalos back into custody Tuesday morning and handed him over to ICE, where officials said he will be held in a federal holding cell – skirting bail reform rules – pending trial.

Donnelly insisted ICE will honor the county’s request not to deport him before trial and would only remove him if he is convicted and serves his sentence.

“This defendant allegedly terrorized communities along the south shore of Nassau County,” she said. “We are going to continue to explore options to upgrade the charges.”

ICE did not immediately respond to The Post’s request for comment.