Inside the standoff: Documents detail suspect's 'erratic' behavior before shooting at Atomic Golf

LAS VEGAS (KTNV) — An Atomic Golf employee had just clocked in for her shift on April 18 when she heard screaming coming from a nearby office.

In the chaos that followed, she was shot through the left side of her chest.

An arrest report obtained by Channel 13 now sheds light on what was going on behind closed doors amid the six-hour police standoff that followed.

The standoff ended with the arrest of Andrew Mullen, a 39-year-old U.S. Army veteran who worked as an armed security guard at Atomic Golf, the arrest report reveals.

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During the standoff, police say Mullen had barricaded himself inside an office on the second floor of the sprawling entertainment complex on the north end of the Las Vegas Strip.

According to the report, surveillance feeds from inside the building gave investigators insight into what led up to the shooting and the barricade that followed.

Mullen, who is originally from Texas, moved to Las Vegas in 2015 with his wife, with whom he has three children. Investigators were told he served in the U.S. Army for five years and was diagnosed with PTSD through the Department of Veterans Affairs. In November 2025, he took a job with a security company and was assigned to work at Atomic Golf.

Mullen's wife told police he was "agitated" when he left for his Saturday shift. He allegedly told her people had been trying to break in and to call law enforcement if she didn't hear from him, according to the report.

"Throughout his shift Andrew became paranoid and sprayed Mace on the floor," investigators wrote. "He believed the chemical smell would keep any dogs and/or people away."

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The report details how Mullen entered an office, turned on the television (according to the report, he specifically told police he selected a "Nazi story"), turned up the volume and took off his shoes to "muffle his footsteps so he did not give away his location."

Screengrabs from surveillance footage included in the report show Mullen "acting erratically" while armed with the revolver he carried during his shift. Investigators note at one point he "appears to be taking cover, sitting in a corner of the office and laying on the floor."

Mullen told police he "became paranoid that Hispanics were going to harm him." When other employees started arriving for the day, he told police he noticed a woman enter the employee breakroom nearby and that "He believed this female was clacking her nails to lure him to fire his ammo until he ran dry."

According to the report, Mullen fired the first shots at 8:07 a.m., through a window that connected the office to the employee breakroom.

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"Once he saw movement, Andrew stated he isolated his target and shot," the report states. "Andrew admitted he later learned while being taken into custody he shot a woman, but she was going to be alright."

The employee Mullen shot told police she and a coworker heard screaming coming from the office, and they tried to open the door because they thought someone was locked inside. In the ensuing confusion, the employee was shot through her left breast, the report states. She and her coworker were able to run out of the building, and she was rushed to the hospital.

In previous statements to media, police described the victim's injuries as non-life-threatening.

Mullen told police he had 15 bullets for his .38 special revolver when he started his shift, the report states, and that "during the course of his shift he had discharged his revolver a total of 12 times."

Police said Mullen pulled over a shelf to block the door to the office, and the ensuing standoff lasted an estimated six hours.

Mullen was booked into the Clark County Detention Center on 13 charges, including battery with a deadly weapon and resisting a public officer with a firearm. He is being held on a $150,000 bond and is expected in court on Tuesday morning.