Inspector Diwakar Sawant, the arrested officer, was attached to the Aarey Colony police station in northern suburbs, police said.
Sawant had demanded Rs 50,000 from the complainant, who is an accused in a case registered at the Aarey Colony police station, for verification of solvent sureties.
The complainant had been granted anticipatory bail. He needed to produce solvent sureties for the bail.
Sawant was caught red-handed today while accepting first instalment of Rs 25,000. He has been booked under the Prevention of Corruption Act.