A 22-year-old youth who worked as a civic volunteer in the Calcutta police has been arrested for allegedly trying to extort money posing as a guard of a deputy commissioner in the city police.

Police said Santu Sarkar, a resident of Jodhpur Gardens, and his uncle Shyamal Biswas were arrested for allegedly running an extortion racket and trying to extort money from a resident of Rahim Ostagar Lane, in the Jodhpur Park area.

The police said they were alerted about Sarkar after a member of the board of administrators of the Calcutta Municipal Corporation received a call on Friday night. The caller, who claimed that he was the guard of a deputy commissioner, complained that the staff of an agency hired by the parking wing of the civic body was harassing him for illegal parking fees though he was driving a “police vehicle”.

“When I asked him to report the matter to the police, he said he was not sure whether the cops would act. That made me feel suspicious. If he were a policeman, why would he say such a thing?” said Ratan De, a member of the board of administrators of the CMC.

“When I questioned him, he became furious and threatened me by dropping the names of senior police officers. I disconnected the phone and reported the matter to the local police station.”

The second complaint against Sarkar was lodged with Lake police station by a resident of Rahim Ostagar Lane. The complainant alleged that Sarkar had tried to extort Rs 2,000 from him by threatening him with dire consequences impersonating as a police officer.

Officers learnt during investigation that Sarkar was neither the guard of any IPS officer nor attached to the division where he said he had been posted. “He was attached to a police station in the south-east division as a civic volunteer,” said an officer.

Sarkar and his uncle were arrested on charges of extortion, cheating, common intention and wrongful restraint on Saturday. Officers said Sarkar would be suspended because of the criminal case against him.

There have been several cases where civic volunteers have tried to extort money from people citing their connections in the police department.

“It is advisable to verify the identity of the person if someone claims to be a police officer or attached to a senior officer as guard,” a senior officer in the city police said.

The police said they were checking if there were any other complaints or cases against Sarkar or his uncle in the crime records section.