The Mumbai police team, which had rushed to the city the day Mukhtar Ahmed was arrested, returned on Tuesday without their “prize catch”, saying they did not want to interrogate him after all.

Calcutta police had said that Mukhtar, arrested in Delhi on charges of procuring SIM cards illegally from Calcutta, would be handed over to the Mumbai police to “trace his terrorist connections”.

But after Mukhtar claimed that he was a constable with the Jammu and Kashmir police’s counter-terrorism wing, the Mumbai police indicated that it would not deal with Mukhtar or take him into its custody. The Jammu and Kashmir police has remained mum on Mukhtar.

Two of the SIM cards bought by Mukhtar from Calcutta were found on two of the slain terrorists in Mumbai.

“The Mumbai police interrogated Mukhtar and Tausif Rehman, who had bought most of the SIM cards, for four days. We allowed them to question the two separately. Mukhtar will be in our custody till December 19 and if Mumbai police want to interrogate him once again within that period, there will be no problem,” said an officer of Calcutta’s police’s Special Task Force (STF).

Rajeev Kumar, the STF chief, said there was no confirmation about Mukhtar’s identity. “We wrote a letter to the director-general of police, Jammu and Kashmir, on Monday requesting him to confirm Mukhtar’s claim about being a police constable, but we have received no feedback yet.”

STF officers insisted on Tuesday that even if Mukhtar was an undercover cop the Jammu and Kashmir police would have to move the court for his release.

“The matter is no longer in our hands,” said an officer. “The court has remanded Mukhtar in police custody and it is for the court to release or detain him.”

STF officers also said they had enough evidence to nail Mukhtar for illegally procuring SIM cards from the city. Tausif had picked up most of the 32 cards using his late uncle’s voter identity card before handing them over to Mukhtar for a premium.

“We have the case sewn up for the charges under which he has been arrested,” said the officer. “We have not branded him a terrorist but merely arrested him for illegally procuring the SIM cards.”

State home secretary Asok Mohan Chakrabarti insisted on Tuesday that “there is no misunderstanding or difference of opinion between us and the Jammu and Kashmir police”, but refused comment on Mukhtar’s identity.