NEW YORK (CBSNewYork) – A Brooklyn man died after being punched during a fight.

Now, police are searching for the suspect who threw the fatal blow.

Police were called around 5:45 p.m. on July 9 to Riegelman Boardwalk East and Brighton 6th Street in Brighton Beach.

Officers found Dimitry Goldfarb, 52, lying on the ground with head trauma. He was taken to the hospital, where he died of his injuries the next day.

“It’s very busy here at 5:45 in the evening. There are a lot of people around, and the sun’s out,” one woman said.

Shirtless suspect seen after deadly attack on Brooklyn man. (Credit: NYPD)

Police were able to speak with Goldfarb before he died, and said he did not know his attacker.

Investigators are still trying to determine exactly what led up to the deadly punch.

“I’m upset because he’s human, he’s a person, but life is life,” said a man in the area. “I’m so sorry about him.”

Andrey Semenoe, the superintendent of Goldfarb’s apartment building, told CBS2’s Aundrea Cline-Thomas that Goldfarb had a large stature and he was surprised a punch could kill him.

“He died? When? It’s true?” he asked Cline-Thomas. “Big guy,  yeah.”

Neighbors said they were shocked, too. Now days later, they didn’t even know Goldfarb was dead, saying he often kept to himself.

“I’m here over 70 years. It’s very rare that you have a murder. You have people fight, but this is ridiculous,” one man said.

The shirtless suspect can be seen on surveillance video walking with a woman after the attack. He’s believed to be in his 30s, approximately 6 feet tall, 220 pounds with long brown hair.

Anyone with information about the attack is asked to call NYPD’s Crime Stoppers hotline at 1-800-577-TIPS (8477) or 1-888-57-PISTA (74782) for Spanish. You can also submit a tip via the Crime Stoppers website, by Tweeting @NYPDTips or by texting a tip to 274637 (CRIMES) and then entering TIP577.