NEW YORK (CBSNewYork) — A good Samaritan who was stabbed after stepping in to try to stop an altercation in Brooklyn on Friday has died.

Police say the incident started around 9:30 p.m. Friday after a robbery in an illegal gambling den in a basement near 57th Street and Seventh Avenue in Sunset Park.

READ MORE: SUV Crashes Into Manhattan Deli Following Collision With Second Vehicle; 6 People Injured

It happened after three men who were robbed ran onto the street after the suspects and confronted them, CBS2’s Kiran Dhillon reports.

Chilling surveillance video appears to show an altercation between two groups of men quickly escalate. The men appear to face off before lunging at one another.

In another surveillance video from across the street, bystanders can be seen stopping to witness the attack.

That’s when police say 46-year-old Yong Zheng, who was returning from dinner with his family, saw what was happening and ran over to help break up the fight.

Instead, he was stabbed four times in the torso.

Video shows Zheng appear to stumble back to his family in shock, holding onto his arm, before collapsing to the ground.

READ MORE: Firefighters Defy Elements, Rescue Man At Base Of Great Falls

He later died at the hospital.

“It’s sad that somebody tried to help somebody and they got stabbed,” one woman said.

Along with Zheng, the three robbery victims were also stabbed. Those three victims, all men in their 30s and 40s, are expected to be OK.

Police are searching for up to three to five male suspects in the case, CBS2’s Christina Fan reported Saturday.

Members of the community  say they’re touched by Zheng’s bravery and how he was trying to help. They’re saddened to hear of his passing.

“That’s super upsetting. That’s a shame that that happened,” one woman said.

Neighbors say they’re sending all their prayers to his family.

MORE NEWS: Police: Woman Wanted For Punching MTA Bus Driver In Manhattan

CBS2’s Christina Fan and Kiran Dhillon contributed to this report.

CBSNewYork Team