Three actors reportedly jumped into the dam, only one swam to safety.
Two Kannada actors are believed to have drowned while shooting a dramatic chase sequence on Monday for which they jumped from a helicopter into a dam around 35 km from Bengaluru.
Stuntmen Anil and Uday, who were shooting for the climax of the film "Masthigudi", never surfaced after plunging into the waters from a height of around 30 feet. The lead actor of the film, Duniya Vijay, also jumped with them but he reportedly had access to a life jacket.
Divers and rescuers have been searching their bodies for hours. Officials fear the actors may have got stuck in silt in the backwaters, which is usually off limits, especially for film shoots.
One of them had tragically confessed before the stunt that he was nervous, but knew there were safety arrangements.
Stunt men Anil and Uday (pictured right) were not wearing lifejackets
The police say the two were not wearing any harness or life jackets, and some on the sets believe they couldn't swim all that well.
"Duniya Vijay had a life jacket but the other two did not," senior police officer Chandragupta told NDTV.
Police sources say the filmmakers and crew may be charged with negligence. There were no rescue boats or life jackets at hand. A team of expert swimmers and officials reached the spot only later.
A small boat with life jackets had been positioned close to the spot where they jumped. It is being investigated why it failed to save the men.