Ismaaiyl Brinsley, 28, ID'd as shooter of two NYPD officers in Brooklyn ambush 'assassinations'

The lone gunman who walked up to a Brooklyn patrol car and opened fire, killing two New York City police officers execution style, has been identified as a Baltimore man who posted chilling anti-cop messages to social media Saturday before traveling to New York to carry out his threats.

Speaking at a press conference Saturday night, New York City Police Commissioner Bill Bratton confirmed the identity of the shooter as 28-year-old Ismaaiyl Brinsley. He identified the two slain cops as partners Wenjian Liu and Rafael Ramos.

Brinsley posted a sinister message on Instagram earlier Saturday along with an image of a silver handgun and hashtags invoking the names of Michael Brown and Eric Garner after reportedly shooting and wounding a former girlfriend in Baltimore.

“I’m Putting Wings On Pigs Today. They Take 1 Of Ours...Let’s Take 2 of Theirs ... This May Be My Final Post...I’m Putting Pigs In A Blanket.” Brinsley wrote, with the hashtags #ShootThePolice #RIPErivGarner #RIPMike Brown.

According to Baltimore police, Brinsley shot and wounded a former girlfriend there around 5:45 a.m. Saturday before traveling to Brooklyn, Bratton said. The woman's mother contacted Baltimore police after she noticed Brinsley's comments on Instagram.

Baltimore police faxed a bulletin describing Brinsley to NYPD headquarters that arrived at 2:45 p.m., Bratton said, at almost the exact moment Brinsley opened fire on Liu and Ramos. Bratton said the ambush was at 2:47 p.m. in Brooklyn's Bedford-Stuyvesant neighborhood.

Bratton said according to a witness, Brinsley took a shooting stance on the passenger side of the police cruiser and fired several times striking both officers in the head. The pair, he said, never had the chance to draw their own weapons and may never have seen their assailant.

“Both officers paid the ultimate sacrifice today,” Bratton said.

Brinsley later fatally shot himself in the head on a subway platform after fleeing the scene.

New York City Mayor Bill de Blasio, speaking after the commissioner, called the attack an "assassination" and said that when a police officer is attacked, every New Yorker should feel as though they were attacked.

“Although we are still learning the details, it’s clear that this was an assassination. These officers were shot execution style,” de Blasio said. “A particularly despicable act … when a police officer is murdered, it tears at the very foundation of our society.”

"Our city is in mourning, our hearts are heavy," he said.

There have been protests almost nightly in New York City since the grand jury decisions in the police-involved deaths of Michael Brown and Eric Garner. Cops in both cases were not indicted.

The mayor has been sharply criticized by New York City police union leaders for comments perceived as unsupportive of the city's police force after an officer investigated in the chokehold death of Staten Island man Eric Garner was not indicted.

Lingering tensions from that fallout were on stark display Saturday night in raw video captured by local television channel PIX11, which showed a wall of officers turning their backs on de Blasio as he arrived at a press conference.

In mid-December, outraged leaders of the Police Benevolent Association (PBA) gathered hundreds of officers' signatures on a form demanding that de Blasio stay away from the funerals of cops killed in the line of duty. The Sergeants Benevolent Association tweeted the below message Saturday:

In a show of solidarity with their fellow members of the forces, LAPD Chief Charlie Beck tweeted that his officers would wear black bands of mourning on their shields.

Rev. Al Sharpton, a Brooklyn native who has taken a prominent role in the protests, condemned the attack on Twitter and reiterated his belief in non-violence.

Sharpton also released a statement saying that the Garner family is outraged by the police killings, and the idea that their son's name and death has been connected to the shooting.

"Any use of the names of Eric Garner and Michael Brown, in connection with any violence or killing of police, is reprehensible and against the pursuit of justice in both cases," the statement said.

Attorney General Eric Holder also released a statement condemning the "senseless shooting":

New Yorkers throughout the five boroughs turned to social media to post eyewitness accounts after routine days were suddenly shattered by the shocking events.

Sabrina de la Torre, who lives in the neighborhood, said she was listening to Christmas music while waiting for the G subway heading to Williamsburg for work, when roughly 20 cops ran onto the platform and screamed for everyone to get down.

“Everyone was very freaked out,” she told Yahoo News. “It was really intense and scary because no one know what was going on. It was a really intense.”

As they ducked down to the ground, de la Torre’s friend, John, shot a video which she then posted to her Instagram page. The view is clearly from the ground and the feet of several cops are seen rushing by in pursuit of the shooter.

“They kept us kind of detained for a while before we found out anyone was shot,” she said.

About an hour after the shooting, LaBasia McBride posted a video on Facebook showing police officers, medical personnel, and crowds gathering near the shooting site.

“This is crazy. Two cops got shot in the head,” a woman can be heard saying in the clip. “Yes, both of them were shot in the head… that’s crazy!”

An Instagram user posted a video showing the commotion at the intersection and a helicopter hovering overhead.

City Councilman Robert Cornegy, who represents Crowns Heights and Bedford-Stuyvesant, said the officers were patrolling public housing complexes as part of a program to increase police presence, DNA Info reports.

"They were just a presence, they weren't over-policing," he said, according to the news site. "They were here as a presence to make the community feel safer."

Many people throughout the country took to Twitter to express deep appreciate for police in the aftermath of the shooting.

The Associated Press contributed to this report.