NEW YORK (CNN) -- A young man carrying what turned out to be a hairbrush died Monday night in a hail of bullets fired by New York police.

Khiel Coppin's brother Joel Coppin spoke briefly with reporters saying, "We want justice."

Authorities were responding to a 9-1-1 call his mother made about a "family dispute with a gun," police said.

In the background of the call, played at a news conference Tuesday, 18-year-old Khiel Coppin can be heard saying, "I've got a gun, I've got a gun," New York Police Department Deputy Commissioner Paul Browne told CNN.

The teen put an object under his shirt and told his mother around the time she phoned 9-1-1 that he was going to say he had a gun, said New York Police Commissioner Raymond Kelly.

The teen told her, " 'I'm prepared to die,' " Kelly told reporters.

When authorities arrived at the Bedford-Stuyvesant apartment, the teenager had something stuffed under his shirt and several times showed a knife to police. "Shoot me, kill me," he shouted, according to Kelly. "Come get me. I have a gun. Let's do this."

Coppin ignored repeated commands to stop and get on the ground. Witnesses said the teen appeared to be holding an object underneath his shirt and pointed it at the officers. Coppin continued to approach officers, as they ordered him to stop, said Kelly.

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Twenty shots were fired; Coppin was struck eight times, Kelly said.

"This was a terrible tragedy for Khiel's family, no doubt about it," said Kelly. But the commissioner stressed that officers reasonably believed they were about to receive fire.

Kelly said the teen's mother reported he had not taken his anti-depressant and anti-psychotic medication.

Police have not recovered a gun and do not believe that Coppin was armed, Kelly said.

A reporter asked Kelly if it's possible the young man was goading police to shoot him, a phenomenon known commonly in law enforcement circles as suicide-by-cop.

"That's certainly a possibility," said Kelly.

"The boy didn't have no gun, he had a brush on him," said Andre Wildman, a neighbor who told CNN that he saw the shooting. Listen to mother's 911 call »

Another neighbor, Wayne Holder, said police should be required to see a weapon before opening fire on a suspect. "At least see a gun before you start to discharge it," Holder said. Police "don't even have to see it, [if] they think you got one, you're going to get shot."

Coppin was taken to a hospital where he was declared dead. An autopsy is scheduled for Tuesday, the medical examiner's office said.

The Rev. Al Sharpton's National Action Network is expected to hold a news conference on Tuesday about the shooting.

Police said they were investigating whether Coppin had a history of mental illness and whether his mother had tried to have him hospitalized earlier Monday.

The shooting came a year after unarmed groom Sean Bell, 23, was killed hours before his wedding in a shooting involving New York police. In 1999, unarmed African immigrant Amadou Diallo, 22, died when police in the Bronx shot him 19 times.

Bystander Dyshawn Gibson described Monday's shooting to CNN affiliate WABC-TV. "He dropped the brush," Gibson said. "He put his hands up. Police just started firing."

Coppin was seen pacing around the apartment prior to the shooting, according to an initial police statement issued Monday night.

"He began screaming from the window at his mother and the police," the police statement said. "At some point, the male climbed out of the window and began crossing the sidewalk toward the police."

That's when police began firing, a police spokesman said. E-mail to a friend

CNN's Jennifer Rizzo, Janine Brady and Alina Cho contributed to this report.

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