Authorities have a person of interest in custody in connection with the brazen shooting of an off-duty New York City police officer who is fighting for his life in a hospital. 

The 26-year-old officer, who has not been identified, is a five-year veteran of the NYPD as well as a father of two young children and a husband. He was shot in the head Saturday night during an attempted armed robbery, authorities said. 

A police source told Fox News the officer is "brain dead."

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Eric Adams

Mayor Eric Adams addresses reporters after the shooting of an off-duty police officer on Feb. 4. A person of interest was in police custody Monday in connection with the shooting.  (NYPD)

The shooting took place around 7 p.m. Saturday on Ruby Street, near Linden Boulevard, the officials said. 

"It hurts a lot," Mayor Eric Adams told the group of reporters Saturday evening, saying the officer is a five-year veteran of the NYPD who was off-duty at the time of the incident. "And it does not dissipate over time."

NYPD Police Commissioner Keechant L. Sewell said the shooting occurred when the officer was conducting "a simple errand" to purchase a used vehicle when a "dangerous person pulled out a firearm" and attempted to rob the officer. There was a gunfire exchange, he said. 

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The officer coordinated the meeting via social media and went with a family member, she said. 

Fox News' Lawrence Richard contributed to this report.