Officer Moore, 25, was in a coma after undergoing brain surgery following the Saturday evening shooting. He was pronounced dead at Jamaica Hospital in Queens on Monday afternoon with his family at his bedside, including a father, uncle and cousin who were police officers.
In announcing his death, NYPD Commissioner Richard Bratton described Officer Moore as an extraordinary man and said his passing is a great loss to the city.
Dozens of uniformed officers stood at attention outside the medical center and lined up down the block to salute the ambulance carrying his body out.
"As a member of the NYPD, Officer Moore put the safety of his fellow New Yorkers before his own, and we will remember his service with gratitude and pride," Gov. Andrew Cuomo said in a statement. "I join with all New Yorkers in mourning his passing and send my deepest condolences to his friends and family."
Charges against he suspect, 35-year-old Demetrius Blackwell, were upgraded to murder after Moore's passing.
"I am deeply saddened by the passing today of New York City Police Officer Brian Moore, who lost his life in the line of duty while protecting and serving our community," Queens District Attorney Richard Brown said in a statement. "Our thoughts and prayers go out to Officer Moore's family and his fellow officers. Officer Moore's death is a stark reminder of the dangers that our police officers face each day and the risks that they take as they carry out their sworn duty to keep our streets safe."
The first-degree murder charge carries a penalty of life in prison without the possibility of parole.
President Barack Obama also responded to the news.
"As many of you know, New York lost one of its finest today in Officer Brian Moore, shot in the line of duty Saturday night," he said. "He passed away earlier today. He came from a family of police officers. And the family of officers, he joined in the NYPD, and across the country deserve our gratitude and our prayers, not just today but every day. They've got a tough job."
Blackwell, who officials say boasted of being a street "hellraiser" and who served prison time for attempted murder, was arraigned Saturday night.
Demetrius Blackwell, 35, was ordered held without bail Sunday after appearing in Queens Criminal Court in a torn white jumpsuit. His hands were cuffed behind his back and legs shackled. Police in Queens Village continue to search for one critical piece of evidence - the gun.
"New York City has lost another brave police officer who placed his life between crime and the good people of the city," PBA President Pat Lynch said. "Brian Moore is a hero in every sense of the word. His loss is felt by all of his brother and sister officers as we pray for Brian and for the loving family that he left behind. His family now becomes our family and we will support them in every way possible through the next difficult days and beyond. I'd like to express the gratitude of all New York City police officers for the support and prayers that have been shown by so many caring New Yorkers. God bless Brian Moore, his family and friends."
Police say Officer Moore and his partner, Officer Erik Jansen, 30, exchanged words with Blackwell before he turned suddenly and fired at least twice, striking Moore. Officer Jansen then radioed for help.
"The man immediately removed the firearm from his waistband and turned in the direction of the officers and deliberately fired several times at the vehicle, striking Officer Moore in the head," Bratton said at a press conference at a Queens hospital.
The shooting took place Saturday around 6:30 p.m. near 212th Street in Queens Village.
"They did not have an opportunity to get out and return fire," the commissioner said at a Saturday night news conference at Jamaica Hospital Medical Center with Mayor Bill de Blasio and other officials.
One woman who did not want to give her name lives in a house in Queens Village that was surrounded by police on Saturday night. The officers were looking for the weapon that Blackwell allegedly used to shoot officer Moore in the head.
Authorities say the plainclothes officers, while riding in their unmarked car, spotted Blackwell, and saw him carrying what they believed was a gun. The officers asked him what he was carrying, and without warning, he allegedly pulled out a gun, and fired. One bullet struck Moore in the face.
The woman watched fellow officers place Moore in another patrol car and rush the officer to the hospital. She says she was standing on her front steps when Blackwell calmly walked up.
"We weren't talking about anything in particular," she said. "We weren't talking about what was going on with this - he was acting totally normal."
By then, teams of officers were looking for the gunman. She says police told her and Blackwell to go inside for safety reasons, and they did. Moments later, everything changed.
"The first SWAT went to this house, and then we saw them coming for ours, guns drawn, they said to open the door," she said.
The woman says officers took Blackwell away in handcuffs.
The married father of three has a lengthy criminal record and just served seven years in prison for attempted murder. He also has arrests for, among other things, robbery and assault.
The two officers, both with about four years on the job, were assigned to an anti-crime unit.
Mayor Bill de Blasio said in a news conference that Officer Moore comes from a police family - his father and uncle both retired as sergeants with the department - and de Blasio praised his service.
"It is a painful day for all of us," de Blasio said. "It is a reminder of the dangers that all of our officers face every single day."