Police officials say Salem will be questioned on his links with film financiers, directors and movie stars.
The likelihood of Salem being brought to India brightened Friday after the Portugal Supreme Court rejected his plea against extradition to the country.
For several years Bollywood personalities had used Salem's gang to recover dues from creditors, say police.
Financiers funded by Salem had also used the mobster's clout to terrorise Bollywood stars to work in their films.
The most prominent case against Salem is his alleged involvement in the murder of music mogul Gulshan Kumar. The juice-shop- owner-turned-music-company owner was allegedly killed by Salem's gang several years ago at the behest of rivals, police say.
Music director Nadeem Saifi, a co-accused in the case, lives in Britain allegedly to avoid arrest by police.
Salem is wanted for the attempt on the life of film producer Rakesh Roshan in 2000. Roshan had refused to give away the overseas rights of his hit movie "Kaho Na Pyaar Hai" to Salem, police say.
Salem is also accused of targeting personalities like Manisha Koirla, J.P. Dutta, Shah Rukh Khan, Amrish Puri, Salman Khan and Preity Zinta.
Police hope the extradition of Salem will lead them to his henchmen and informers in the film industry who constantly provided him with inside information on film personalities.
Struggling movie stars, star secretaries, technicians are among several others believed to have informed Salem
on the developments in Bollywood.Police say Salem used his network to carry on his extortion activities though he lived abroad for more than 10 years.
Salem fled the country shortly after the 1993 serial bomb blasts that rocked Mumbai, claiming nearly 300 lives.
He, however, conducted his extortion activities as part of the Dawood Ibrahim gang before falling out with his boss a few years ago.
