(CNN)An unprovoked stabbing attack of a New York Police Department officer that ended with two other officers with gunshot wounds and a suspect in critical condition is being investigated as a possible act of terrorism, a source familiar with the matter told CNN.
Attack on NYPD officers being investigated as possible act of terrorism, source says
Investigators do not believe the alleged acts are affiliated with any protests or looting seen across the city, the source said.
The incident began around 11:45 p.m. Wednesday, when a man "casually" walked up to two officers at an anti-looting post in Brooklyn, took out a knife and stabbed an officer in the neck, Shea said during a press conference, citing video surveillance of the incident.
"That officer was stabbed in the left side of his neck, thank God, missing an artery, and is recovering here in stable condition at the hospital," he told reporters early Thursday morning.
At around the same time, a uniformed sergeant and a police officer who were "a block or two away" heard shots fired and responded to the scene near the post at the intersection of Church and Flatbush Avenue, Shea explained.
"We believe that when they got there, they saw the perpetrator with a gun in his hand, which we believe belonged to one of the officers. What we know at this point in time is that 22 shell casings have been recovered from a number of members of the service," Shea said.
He described the scene as "chaotic" and noted that a knife was recovered.
In the shooting, the man was struck multiple times and is in critical condition at Kings County Hospital in Brooklyn, according to the police commissioner.
Two officers were shot in the hand. All three injured officers are in stable condition and are expected to recover, Shea said.
The Joint Terrorism Task Force is investigating whether the incident is linked to terrorism, the source told CNN.
Investigators are looking into social media accounts affiliated with the suspect, the source said. As of early Thursday morning, JTTF investigators had not spoken with the man, according to the source.
The FBI's New York office is "fully engaged" and working to hold the suspect accountable.
"We respond as if one of our own was attacked, and we will use every federal statute available to hold the perpetrator accountable," FBI New York Assistant Director in Charge William Sweeney said in a tweet Thursday morning.
The stabbing had "all the hallmarks of something that would be out of the terrorist playbook," said John Miller, the NYPD's deputy commissioner of intelligence and counterterrorism, at a news briefing Saturday.
The type of attack — described by Miller as a sudden lunging towards the officer's neck with a knife — had similarities to attacks against police officers in Europe, Miller said. The tactic is seen in training videos from groups like ISIS, he said.
Miller said the assailant yelled "Allahu akbar" as he stabbed the officer's neck.
Investigators have not been able to interview the alleged attacker because he has been intubated, Miller said, adding he had a limited social media presence.
New York City Mayor Bill de Blasio called the incident a "painful, horrible moment." The officer who was attacked with a knife was born in Haiti, he said.
"Any one of the attacks on one of our officers is an attack on all of us," he said.
The incident came during a week of protests calling for an end to police violence against black people, spurred most acutely by the police killings of George Floyd in Minneapolis, Minnesota, and Breonna Taylor in Louisville, Kentucky.
In New York City, large groups of protesters have marched in the streets, chanting phrases such as "black lives matter" and "no justice, no peace." Amid the protests, some people have looted stores or damaged property, and some protests have devolved into violence both by police and against police.
On Thursday morning, Shea told CNN he supported protesters' right to peacefully assemble but not any violence.
"I cannot even tell you how many officers have been attacked in the last week. It has been a very dangerous time," Shea said.