The investigation into the Salman Khan-Aishwarya Rai audio tape, in which the actor boasted of his underworld connections, may face hurdles with the Mumbai police commissioner on Thursday saying that the police did not have a record of the phone tappings of Salman's cell when it was under surveillance on suspicion of being used to talk to gangster Abu Salem [Images].

"The record of conversations taped during surveillance has not been maintained for four years. As per Supreme Court directions, such tapes are regularly destroyed," Mumbai Police Commissioner A N Roy told reporters in Mumbai on Thursday.

• CBI asks Mumbai police for Salman tapes

According to Roy, the police had placed a cell phone under surveillance in August 2001 on the suspicion that it was being used to contact Salem. It was eventually found that the cell belonged to Salman, he said.

"We tapped the phone for two months after taking due permission, but at the end did not find anything suspicious," he said clarifying why the conversation tapes could have been destroyed then.

• Salman called gangster in 01, says Maharashtra home minister

Roy, however, said that the ongoing probe will continue to find out if the purported audio tape was a police tape, and whether somebody leaked it.

The Maharashtra government on Wednesday ordered a probe into the matter led by Additional Commissioner of Police K L Bishnoi that would ascertain the veracity of the alleged conversation, and check if Salman indeed has underworld links.

Deputy Chief Minister R R Patil, who also holds the Home portfolio, had on Wednesday made a statement in the Legislative Assembly, wherein he said that the state would take legal advice on the issue if required.