Police Commissioner Raymond Kelly said the 18-year-old pointed the brush at the officers "as if he were aiming a gun," and repeatedly ignored orders to "stop, show his hands, and get on the ground."
The district attorney is investigating, but Kelly said that officers reasonably believed Coppin was about to use deadly force and that their response appeared to be within NYPD guidelines.
Kelly also said Coppin had brandished a pair of knives when officers first arrived, at one point taunting police by saying: "Come get me. I have a gun. Let's do this."
Coppin's family denounced the Police Department for quickly concluding that the officers were justified in their response.
"Nobody but Houdini himself could have decided that in 24 hours," said the family's lawyer, Paul Wooten.
The 17-minute altercation began about 7 p.m. Monday when officers arrived at the Brooklyn home in response to a report of a dispute involving a gun. The mother, Denise Owens, had summoned a psychiatric intervention team earlier in the day, saying her son was suicidal, but he left before the team arrived, Kelly said.
In the 911 call, while the emergency operator took down the address in Bedford-Stuyvesant, a male voice was overheard in the background, saying, "I got a gun and I'm going to shoot you."
When a 911 operator called back about five minutes later to ask Owens for a description of her son and the weapon, she told the operator, "He does not have a firearm," a second transcript shows.
"I'm flipping out," the mother added. "I can't handle this."
When officers arrived at the home, they said they encountered Coppin inside with knives. They backed off and ordered his mother and younger sister outside.
The teen began screaming from a first-floor window at his mother and officers before climbing out the apartment window and crossing a sidewalk toward the officers while holding the hairbrush in his hand, police said.
The officers backed up and ordered him to stop, police said. When the teen refused and kept approaching them, they began shooting from a distance of 5 to 7 feet, police said. Police said eight of the 20 bullets struck Coppin, who was pronounced dead at a hospital.
"This was a terrible tragedy for Khiel's family," Kelly said.
