That led the officers to fire 10 shots.
Video released by police show that in the moments before his death, Vassell had been brandishing the bent pipe like a gun and had pointed it at people on the street.
The New York State attorney general's office said on Thursday it would investigate the fatal shooting by police of an unarmed black man in Brooklyn after he pointed a metal pipe at officers that they believed was a gun.
A tense crowd gathered after the shooting, with some people shouting at officers and decrying the killing as another example of an unarmed black man being killed by police officers who overreacted.
Authorities, however, did not warn Vassell before they shot at him, according to one eyewitness, who compared the shooting to a "hit" in a New York Daily News report.
NY state's attorney general, Eric Schneiderman, announced that he would investigate the shooting. The cops were responding to 911 calls, reporting a black man in a jacket pointing a "silver firearm" at people, who NYPD Chief of Patrol Terence Monahan says "took a two-handed shooting stance" and pointed at them, according to several USA media reports.
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Timothy's family stated that he had a conversation with them the day before he vanished, that had left them concerned. In the statement , it said that Cunningham had in fact received an early promotion for his outstanding work.
Police said the responding officers were from a strategic response group and an anti-crime unit, not from the local 71st Precinct and not familiar with Vassell, who was a popular fixture in the community. "We need to figure out why", said Williams.
In another 911 call, another caller reported: "There's a guy walking around the street. He looks like he's insane, but he's pointing something at people that looks like a gun", one caller tells the dispatcher. "Police always have a choice", he told WABC in an interview Thursday.
In police radio traffic recorded during the incident and posted online, dispatchers directing officers to the scene said 911 callers were reporting only that a person was pointing a gun at people. They should not train them to kill. "We know that any concern over Mr. Vassell's condition should have been met with mental health supports and that is not the role that police are trained to play".
One clip shows the man holding the object in what police described as a "two-handed shooting stance" as officers arrived. Last month in Sacramento, California, 22-year-old Stephon Clark was shot and killed by officers who believed he was armed with a gun, but all that was found on him was a cell phone.
Before shooting, the officers yelled at Vassell to "drop it, drop it", the officials said about the incident that happened in "seconds". Messages will be in English and Spanish, with other languages soon to be added, said Susan Herman, the NYPD's deputy commissioner for collaborative policing.