Woman Arrested in Casino Garage Over Mass Shooting Plot

Police in Henderson, Nevada, arrested a woman accused of plotting a mass shooting after intercepting her in a casino parking garage. Authorities announced the arrest Tuesday, revealing that officers had seized more than 50 firearms combined from her vehicle and home. The suspect, 36-year-old Allison Howlett, was taken into custody Saturday, June 27, in the parking structure of Sunset Station Casino in Henderson, about 10 miles from the Las Vegas Strip. Law enforcement credited quick coordination for preventing a potential mass-casualty event.

911 Call on Gun Threat Leads Police to Casino Parking Garage

Henderson police first learned of the threat Saturday morning. A woman called 911 at 9:38 a.m., reporting that her ex-spouse had stolen her vehicle, which held multiple firearms.

The caller warned dispatchers that Howlett had threatened to carry out a mass shooting and commit suicide by cop.

Officers arrived at the caller's home around 10 a.m. and found that the car had a GPS tracker. That device led police to the area near Sunset Station Casino. By 11:17 a.m., Henderson officers, along with casino security, had located the vehicle inside the parking garage. Howlett sat in the driver's seat, playing loud music and ignoring commands to exit. Patrol cars boxed in the vehicle to block any escape attempt.

Standoff Ends in Arrest, 52 Guns Seized

Police negotiators eventually got Howlett to lower the window. When she asked for water, officers seized the opportunity. They grabbed her hand as she reached for the bottle, then tased her to remove her from the vehicle safely. She was sitting on a handgun at the time. A fully automatic, silenced MP5-style submachine gun sat in the back seat, according to police. Investigators recovered 22 firearms and hundreds of rounds of ammunition from the car. A search of her Henderson residence turned up 30 more firearms, including automatic rifles and suppressors, bringing the total to 52 weapons.

Terrorism Unit Investigates Prior Threats, Charges Filed

After the arrest, Henderson police contacted LVMPD's Southern Nevada Counter Terrorism Center. Investigators identified several threats Howlett allegedly made over the years, including explicit statements about becoming an active shooter. At Tuesday's briefing, authorities played a 2024 audio recording of a voice they identified as Howlett's. In it, the speaker threatened a mass shooting if federal agents did not intervene.

FBI Special Agent in Charge Christopher Delzotto praised the swift coordination between Henderson police, LVMPD, and federal partners. Howlett now faces charges including a terrorism-related threat, assault with a deadly weapon constituting domestic violence, grand larceny of a vehicle and firearm, and resisting an officer with a firearm. Her arraignment was scheduled for Wednesday morning in Henderson Justice Court.