An accused transgender terror plotter who allegedly planned a massacre at a Las Vegas-area casino had threatened a mass shooting years earlier, according to chilling audio recordings released by police.

Allison Howlett, 36, who was born male but lives as a woman, was arrested Saturday with a massive cache of guns and ammunition in a casino parking garage in Henderson just outside Las Vegas.

The suspect’s former spouse had called police to report that Howlett intended to commit “suicide by cop” or carry out a mass shooting, Henderson Police Chief Reggie Rader said.

After the arrest, authorities revealed that Howlett threated of a mass shooting as far back as 2024, playing an audio recording of the suspect unleashing a frightening foul-mouthed rant.

“I swear to God, if the FBI doesn’t come f—king arrest me, there’s gonna be a f—king mass shooting,” Howlett is heard saying in the recording, according to law enforcement.

Howlett then grows more agitated, adding: “There’s one day you’re gonna be pissing me the f—k off, and it’s gonna be the last f—king straw.

“You’re going to the be reason that hundreds of people lose their goddamn life.”

Officers did not identify the source of the recording or who Howlett had been speaking to.

Howlett was arrested Saturday charges of making terroristic threats, assault with a deadly weapon, auto theft, gun theft and other offenses.

Video of the arrest at the Sunset Station hotel shows officers surrounding Howlett’s vehicle and dragging the suspect from the car.

Officers were shocked to see Howlett had been sitting on a handgun and had an MP5 submachine gun in the back seat.

Police said they uncovered a total of 55 firearms, with 22 of them from the vehicle and the rest from Howlett’s residence. Multiple handguns, rifles, a fully automatic firearm, suppressors and hundreds of rounds of ammunition were discovered in the car.

Howlett remains in custody on $500,000 bail. A judge on Wednesday set a preliminary hearing for July 15.