The man was standing near a hotel in Wagle Estate area here on November 20 evening when the trio approached him.
They accused the man of eve-teasing and then forcibly took him away in an auto-rickshaw, the official from Wagle Estate police station said quoting the complaint.
The accused drove the auto-rickshaw to an isolated place where they closed the man's eyes with a piece of cloth and snatched ₹8,000 from him. They also forced him to transfer ₹40,000 from his bank account to their account, the police said.
The accused later pushed the man out of the auto-rickshaw near Nitin Company junction in the city, the complainant alleged.
Based on the complaint, the police on Wednesday registered a case against the unidentified persons under Indian Penal Code sections 386 (extortion), 364A (kidnapping for ransom), 392 (robbery) and 34 (common intention) and a probe was on into it, the official said.