The policemen, attached with Narpoli police station, had detained Istiaque Makbul Ahmed Chowdhari, a local builder, his son Abdul Mabud alias Sonu and their neighbour Mefuz Alam on May 7 for their alleged involvement in theft of yarn from a container, senior inspector Anil Akhade said today.
The three were detained in the police station till the next morning, Akhade said quoting the complaint filed by Chowdhari.
The accused extorted money in instalments from the three persons, the police officer said.
Based on the complaint, offences were registered yesterday against the four policemen under sections 342 (wrongful confinement) and 384 (extortion) rw 34 (acts done by several persons in furtherance of common intention) of the IPC, he said.
The investigation in the case was being carried out by the Anti-Extortion Cell of Thane's crime branch, he said, adding that no arrest has been made so far in this connection.