New York City Police Officer Brian Moore died Monday at Jamaica Hospital in Queens from head wounds sustained when a man opened fire Saturday in Queens Village, sources told the New York Daily News. Moore was 25 years old. The New York Police Department's 106th Precinct confirmed Moore's death on Twitter.

Demetrius Blackwell, a 35-year-old Queens man, was arrested in the shooting and arraigned in criminal court Sunday on charges of attempted murder and criminal weapons possession. Blackwell did not enter a plea and was due to return to court on Friday. He is expected to face murder charges now that Moore is dead, the Daily News reports.

Moore was hospitalized for two days after the shooting. He remained in critical condition late Sunday after four hours of brain surgery. A bullet hit Moore in the forehead and caused grave brain damage, a source told the New York Post. Moore suffered “severe injuries to his skull and brain and was “fighting for his life” Sunday, Queens District Attorney Richard Brown told the Associated Press.

Moore was dressed in regular clothes when he and his partner observed Blackwell engaging in strange behavior on Saturday in Queens Village. The officers observed Blackwell fidgeting with his waistband and were aware that he had a criminal record.

The pair drove their car toward Blackwell, who reportedly opened fire with a handgun. Moore’s partner was unhurt, but Moore was struck in the head with a bullet.

“[Blackwell] immediately opened fire on them before they had a chance to get out of the vehicle,” Police Commissioner Bill Bratton said at a Sunday press conference.

Blackwell fled the scene, but NYPD officers were able to locate and arrest him with help from witnesses. Authorities were unable to locate a firearm. Three people identified Blackwell, according to the Post. He is being held without bail.

“All I heard was shots and an officer screaming for his partner and saying, ‘Stay with me!’” a bystander told the Post.