(MCLEAN Va.) — An off-duty U.S. Park Police officer was arrested Sunday and charged with fatally shooting a colleague inside a McLean, Virginia, apartment while allegedly handling a gun he thought was unloaded during an alcohol-fueled get-together, authorities said.

U.S. Park Police officer Alexander Roy was charged with involuntary manslaughter in the killing of fellow U.S. Park Police officer Jesse Brown Hernandez, according to the Fairfax County Police Department.

The shooting unfolded about 12:20 a.m. local time on Sunday when the 25-year-old Roy was playing around with a gun he assumed was empty, hitting the 22-year-old Hernandez in the upper body, officials said.

“Roy unintentionally shot the firearm he believed to be unloaded, fatally striking Hernandez,” the Fairfax County Police Department said in a statement. “Alcohol is believed to be a factor in the shooting.”

At the time of the shooting, three of the four individuals inside the apartment were off-duty U.S. Park Police officers, officials said.

Fairfax County officers went to the apartment after receiving a 911 call reporting an adult male had been unintentionally shot, officials said.

When officers arrived at the residence, they found Hernandez dead at the scene, according to authorities.

A preliminary investigation indicated that Roy was allegedly “dry firing” the weapon, or attempting to simulate the discharge of a firearm by pulling the trigger of the gun he thought was unloaded, according to the Fairfax County Police Department.

After consulting with prosecutors, Roy was charged with Involuntary manslaughter. He was being held without bond Sunday at the Fairfax County Adult Detention Center.

“We are aware of the incident involving off-duty United States Park Police (USPP) employees at a private residence in Fairfax County,” the U.S. Park Police said in a statement. “The incident is under investigation by the Fairfax County Police Department and all questions related to this investigation will need to be referred to them. Our focus right now is on supporting the family, friends and coworkers of our employees involved in this tragic incident. USPP has nothing further to share at this time.”

The circumstances of the shooting remain under investigation and the Fairfax County Police detectives asked that anyone with information about the incident to contact them immediately.

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