U.S. Park Police officer unintentionally fatally shoots fellow officer at Virginia gathering, police say

An off-duty U.S. Park Police officer unintentionally shot and killed another off-duty officer over the weekend in Virginia as he pulled a trigger on a gun he thought was unloaded, police said.

Alexander Roy, 25, was charged with involuntary manslaughter in the death of Jesse Brown Hernandez, 22, while they were at a gathering in an apartment in McLean, Virginia, about 10 miles west of Washington.

Police were called to the scene shortly after midnight on Sunday.

Two other people, including another U.S. Park Police officer, were also at the gathering. Police said alcohol is believed to be a factor in the shooting. Roy is being held at the Fairfax County Adult Detention Center on no bond.

Hernandez was found dead with a gunshot wound to the upper body. The investigation continues, and Fairfax County police ask anyone with information about the incident to contact them.

The Park Police serve the National Park Service and neighboring communities. They also provide security for the president, the interior secretary and visiting dignitaries.

Park Police said in a news release that they are aware of the incident and directed all questions about the investigation to Fairfax County police.

"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," Park Police said in a statement.

This article was originally published on NBCNews.com