The victims are believed to be Gurmeet Ram Rahim Singh’s followers. Angry supporters are rampaging through Panchkula town.
Reports of widespread vandalism are coming in. At least two railway stations have been set on fire.
Followers also smashed cars and set media vans alight.
Singh, who claims to have millions of disciples, was found guilty of raping two women at the headquarters of his sect, known as Dera Sacha Sauda, in 2002.
More than 200,000 of his followers had flocked to the Chandigarh area ahead of Friday’s verdict.
Thousands of army, police and paramilitary forces have been deployed. They are firing tear-gas canisters and water cannon into the crowd to try to restore control, says the BBC’s Robin Singh in Panchkula.
At least a dozen people have been injured in the town.
Curfews have been imposed in several areas of the city and across the state of Punjab.
Meanwhile, violence has also spread to the capital, Delhi, where two train coaches have been set on fire, according to reports.
Singh, 50, was taken into protective custody by the army following the conviction.
The court is expected to sentence him on Monday.
Who is Gurmeet Ram Rahim Singh?
Controversial leader of the Dera Sacha Sauda sect, which claims to have 60 million followers around the world
Took over the sect – which describes itself as “a non-profit social welfare and spiritual organisation – when he was 23
Performs at rock concerts, acts in films and even has his own line of food products
Known as “rockstar baba” and “guru of bling” because of his shiny, colourful clothes
Has been accused of mocking Sikh and Hindu figures
Has been investigated for murder and rape, charges he denies
Has been accused of forcing followers to undergo castration to “get closer to god”
Punjab Chief Minister Amarinder Singh criticised his counterpart in the state of Haryana for allowing so many of Singh’s followers to travel to Chandigarh.
Chandigarh is the capital of both states.
The border between the two states has been sealed.