By Zubair Ahmed
BBC correspondent in Mumbai
Bollywood star Aishwarya Rai has been questioned over allegations that fellow actor Salman Khan had boasted to her of his links to underworld criminals.
Aishwarya Rai was questioned by police
Khan allegedly made the remarks in a secretly taped phone conversation four years ago.
Lawyers for Salman Khan have said the voice on the tapes was not that of their client.
Voice samples of both actors have been collected in an attempt to match them with the ones on the tape.
Police in the city of Mumbai (Bombay) questioned Ms Rai on Monday. The voice samples taken from her and Mr Khan are being sent to Delhi for examination.
Last week the Hindustan Times newspaper published transcripts of a secretly recorded conversation and claimed that the call had been made to Ms Rai by Mr Khan.
Mumbai police commissioner AN Roy confirmed his department had not recorded the conversation.
Under Indian law, court permission has to be taken in order to tap anyone's phone.
It is not clear who recorded the conversation and whether permission was sought before recording.
Police say they are looking into these aspects as well.
Experts say even if the conversation is authentic it will be difficult to use it as legal evidence in court.
Salman Khan, who was questioned on Sunday, told the police that he never made the alleged call to Aishwarya Rai.
He said he had no connection with underworld criminals and had never met anyone of them.