Authorities say suspect arrested at Henderson casino planned mass shooting

A heavily armed suspect who authorities said had planned a mass shooting was arrested in a Henderson casino parking garage over the weekend, police announced Tuesday.

Allison Howlett was arrested Saturday on suspicion of making a threat related to an act of terrorism, assault with a deadly weapon constituting domestic violence, grand larceny of a motor vehicle, grand larceny of a gun, resisting a public officer with a firearm and other offenses, Henderson Police Department Chief Reggie Rader said during a press conference at the Metropolitan Police Department headquarters near downtown Las Vegas.

Howlett was described during as the briefing as both female and male. Jail records list Howlett as male, and a Metro representative was not available to clarify Howlett’s gender.

Rader and Metro officials said a woman called police shortly after 9:30 a.m. Saturday to report a domestic dispute. The caller, Howlett’s former spouse, stated that Howlett had stolen her car and that the vehicle held numerous firearms, Rader said. The caller added that Howlett intended to commit “suicide by cop” or carry out a mass shooting, the chief said.

The woman told 911 she did not know where Howlett was headed, according to Rader. The chief said officers arrived at the woman’s residence shortly before 10 a.m. and learned the caller had been tracking the vehicle.

“The vehicle tracking showed it was mobile until stopping in the general vicinity of Warm Springs Road and Stephanie Street,” Rader said.

Officers began searching the area, and Howlett was located in the parking garage at Sunset Station by hotel security at 11:17 a.m. Saturday, Rader said.

Rader said Howlett was playing music loudly inside the vehicle as officers approached, and that Howlett refused commands to exit the vehicle. Officers eventually surrounded the vehicle and apprehended Howlett after Howlett asked for water.

“Officers were eventually able to establish communication and convince her to roll down her window during negotiations,” Rader said. “When she asked for water, the quick-thinking officers developed a plan to take her into custody as an opportunity arose when she reached for the water. Officers used that moment to gain control of her hands and remove her from the vehicle.”

Rader said Howlett was stunned once with a Taser while being taken into custody. Authorities at the briefing also played body camera footage of an officer taking Howlett into custody.

“Ow, OK, I’ll get out,” Howlett said after an officer grabbed one of Howlett’s hands sticking out from the driver’s side window of the blue sedan they were in.

Police: Howlett had 22 guns in back of vehicle

Officials said Howlett was sitting on a handgun and had an MP5 submachine gun in the back of the vehicle.

Metro Assistant Sheriff Dori Koren said Metro’s Counterterrorism Section and the FBI’s Joint Terrorism Task Force identified several threats made by Howlett going back years, and played an audio recording of Howlett from 2024 making a threat to carry out a mass shooting.

Authorities did not identify the source of the recording.

“I swear to God, if the FBI doesn’t come f——— arrest me, there’s gonna be a f——— mass shooting,” Howlett said in the 2024 recording played at Tuesday’s briefing.

The recording continued: “There’s one day you’re gonna be p——- me the f—- off, and it’s gonna be the last f——— straw. I swear to God, (redacted), you’re going to be the reason hundreds of people lose their God d—- life.”

Koren said officers executed a search warrant on the vehicle and recovered 22 other guns and hundreds of rounds of ammunition. Officers also searched Howlett’s residence in Henderson, where investigators recovered an additional 30 firearms, including automatic rifles, as well as grenade launcher attachments, suppressors and magazines.

Police still seeking motive, Koren said

Koren said the incident remains under investigation and that investigators are still seeking a potential motive.

Christopher Delzotto, the Special Agent in Charge of the FBI field office in Las Vegas, said Howlett’s arrest has not yet resulted in federal charges, but credited Howlett’s arrest to the swift collaboration of local law enforcement.

Howlett, 36, remained in custody at the Clark County Detention Center, jail records show.

Howlett is scheduled to appear for arraignment at 9 a.m. Wednesday in Henderson Justice Court. An attorney is not listed on Howlett’s case overview.

If you’re thinking about suicide, or are worried about a friend or loved one, help is available 24/7 by calling or texting the Lifeline network at 988. Live chat is available at 988lifeline.org. Additionally, the Crisis Text Line is a free, national service available 24/7. Text HOME to 741741.