By Sanjeev Srivastava BBC India correspondent

One of Bollywood's worst-kept secrets - the connections between the Bombay film industry and the criminal underworld - have been thrown into the spotlight again.

Funding for Bollywood films is often difficult

Top Bollywood financier, Bharat Shah, and producer, Nasim Rizvi, have been convicted of withholding information from the police about links between the Indian film industry and the mafia.

Shah was cleared of the more serious allegations linking him with criminal activities of the underworld.

Despite the court verdict, which has resulted in a one-year jail sentence for Shah - his friends in the film industry continue to back him.

Veteran Indian film maker, Mahesh Bhatt, told the BBC that the substantive charges against the Bollywood financier - of direct links with the mafia - have not not withstood judicial scrutiny.

There's hardly anybody in the film industry who has - at some stage of his or her career - not been contacted by the mafia Mahesh Bhatt

"It just proves that it was a political case slapped against him because he had dared to take on some powerful governing party politicians," he said.

On the issue of withholding information from the police on some conversations with alleged underworld figures, Mr. Bhatt said on that count the entire Indian film industry should be in the dock.

"There's hardly anybody in the film industry who has - at some stage of his or her career - not been contacted by the mafia either through telephone or some conduit," said Mr Bhatt.

"Who can dare to refuse to take a call from the underworld. And who will report such matters to the police and invite further trouble?" he told the BBC.

But those associated with the Indian film industry say matters are not always as straightforward.

Risky ventures

A number of Bollywood stars and film producers are alleged to have close links with mafia dons.

One such case involving a top Bollywood star - whose parents were even bigger names in Bollywood in the 1950s and 1960s - has been dragging on for nearly a decade.

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There are other cases where Bollywood stars are alleged to have used their underworld connections to bag coveted roles.

Stars have become more discreet in the last decade or so, since the police have turned up the heat on the alleged mafia-Bollywood nexus.

But not long ago, it was quite common for stars to openly flaunt their mafia connections.

Some of the biggest names of Bollywood were regularly seen in the company of underworld figures at cricket matches and parties.

Other than the very obvious glamour and glitter angle, mafia dons also saw a business opportunity in a film industry which was always in need of funds.

Funding is still not very easy to come by, but until a few years ago, there was absolutely no institutional financing as film-making was seen as a highly risky venture.

And rightfully so, as most films sank without trace at the box office and only a few recouped their production costs.