WILLIAMSBURG — The family of a Brooklyn real estate developer police believe was kidnapped outside his office Thursday night has offered a $100,000 reward for his safe return, no questions asked, his brother said Friday.

Menachem Stark, 39, left his office, Southside Associates, at 331 Rutledge Street at 11:35 Thursday night and was walking to his car parked nearby when two men approached him, fought with him for about two minute and drove him away in a white or light-colored minivan, according to police.

Stark's wife, Bashie, became worried when he did not come home before midnight and notified the Shomrim, a neighborhood watch group for the Orthodox community.

Shomrim alerted police at 2:30 a.m. on Friday.

Security video shows Stark grappling with two two men before being pulled into the van and driven off.

NYPD investigators canvassed Rutledge Street on Friday morning, pulling security footage from multiple security cameras near the scene of the kidnapping and speaking to local business owners.

"We're waiting for a phone call with demands. [We're] just hoping that he is still alive," his brother Yitzy Stark, 30, said. "We'll do anything they ask."