Police are searching for multiple people after a 16-year-old Long Island boy was stabbed to death during a brutal beating that was captured on video by a group of his peers.

Khaseen Morris died just before midnight Monday of a stab wound after a brawl outside a strip mall in Oceanside, New York, Nassau County Police Det. Lt. Stephen Fitzpatrick said at a news conference Tuesday.

Fitzpatrick said six or seven people attacked Morris and his friends while between 50 and 70 onlookers watched and some recorded the melee on their phones. Footage of the incident circulated on Snapchat and other social media platforms.

"Kids stood here and didn't help Khaseen," Fitzpatrick said. "They videoed his death instead of helping him."

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Morris was a senior at at Oceanside High School, school district spokesperson Donna M. Kraus confirmed.

"The community is shocked and saddened by this tragedy," Kraus said. "We have counselors supporting our students and we’ve reached out to Khaseen’s family."

Fitzpatrick said the fight was sparked by "a dispute over a young lady" that Morris was seen with. Keyanna Morris, 30, told Newsday that her brother had walked a girl home and had been threatened by the girl's ex-boyfriend. Keyanna Morris said Khaseen wasn't worried.

"Khaseen is like, ‘OK, if you beat me up, fine.’” she told the outlet. "No one knew he was going to bring a million people out there — and a knife."

Fitzpatrick confirmed that Morris had been threatened through social media, and that he was unarmed even though he knew that someone might show up to assault him after school.

One of Morris' friends was left with a broken arm; others suffered minor injuries, Fitzpatrick said. He said that some witnesses have come forward and helped identify suspects but that there are "definitely" more people involved.

He urged anyone who has information about the brawl to share it with the police.

"This can't go on," Fitzpatrick said. "Your friends are dying while you stand there and video it. This is egregious."

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