The actor is facing trial in a Jodhpur court on charges of killing a black buck and chinkaras (Indian gazel) while shooting for 'Hum Saath Saath Hain' in 1992.
Salman was sentenced to imprisonment in April last year. After spending 71 hours in jail as prisoner number 210, Salman won bail from a higher court.
"Quaidi Number 210", the movie based on the case, is expected to star real characters, including the lawyers who are fighting the case. Jodhpur-based Kamal Srimali has written the script for the film.
Sharma, who has earlier made a film on the life of bargirls, was in Jodhpur recently to finalise locations and sign characters.
"Barring Rahul Roy, who will play Salman in the film, we wish to cast real characters of the story to make the film as original as possible," Sharma said.
He added that the Jodhpur central jail administration had granted him permission to shoot inside the prison.
Sharma has started approaching people involved in the case. He has already signed the driver of the Maruti Gypsy used in the killing of the animals.
Hastimal Sarawat, Salman's advocate, confirmed that Sharma approached him for a role but he said he would not make a decision without going through the script.
"I want to make sure the film will not harm my client in any which way. Also, it should not show anything which might influence the trial," he said.
Mahipal Bishnoi, who has fought the case as a representative of the Bishnoi community, is also unsure about acting in the film. "It all depends on what they what to show. Let me read through the script," he said.
The Bishnoi community of Rajasthan worships the black buck. The area where the animals were killed is populated by Bishnois.
However, Sharma is confident he would be able to win them over and he hopes the film will hit theatres early next year.