Though Kunal Vardhan, son of Champalal Vardhan, joint managing director of Neelam Realtors and part owner of Worli's Atria mall, took the victim - production manager Mayur Kadam - to Bombay Hospital, he did not report the accident to the police.
The accident happened near the Trident hotel at about 11.30pm.
The driver of the Mercedes, Vardhan, apparently lost control of his vehicle and rammed into the two-wheeler Kadam was riding.
"Wardhan and some people passing by took Kadam to Bombay hospital," said a police officer of Marine Drive police station.
The police have registered a case against Wardhan under section 304(A) of the IPC for causing death due to rash and negligent driving.
Ravindra Shisve, deputy commissioner of police (zone-1) said the police were inquiring into the incident. No arrest has been made so far.