A 63-year-old rabbi who was working out in a Brooklyn park on Tuesday morning was suddenly attacked, according to police, who say the suspect hit the grandfather's face with a rock. The NYPD is investigating this as a possible hate crime.

The victim, Abraham Gopin, suffered a broken nose and also lost two of his teeth.

The attack took place around 7:40 a.m. According to the police, Gopin had been working out in Lincoln Terrace Park, at 398 Buffalo Avenue in Crown Heights, "when an unidentified male began to punch him." Gopin tried to defend himself, but the suspect allegedly used a rock to strike him in the face before fleeing.

A video of a person wanted for questioning was released:

While the police say there was no interaction or verbal exchange between Gopin and the attacker, Gopin's family says that the suspect used a racial slur before punching him.

"He certainly feared for his life," Gopin's son-in-law, Benny Friedman, told WCBS 2. "It was clear to him that the man was trying to kill him. Those were his words – the man was out for blood, that’s for sure."

In an interview with WABC 7, Friedman said the suspect "was yelling 'dirty Jew', which makes it very painful."

Mayor Bill de Blasio tweeted, "The NYPD Hate Crimes Task Force is investigating this despicable act of violence, and we will find the attacker. This city will stop at nothing to protect our communities from hate and violence."

The Anti-Defamation League of New York and New Jersey is also offering a $5,000 reward.

Anyone with information in regard to the identity of this male is asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782). The public can also submit their tips by logging onto the CrimeStoppers website at WWW.NYPDCRIMESTOPPERS.COM, on Twitter @NYPDTips.