Chandigarh, Sept. 4 -- A young anti-drug campaigner who was detained after displaying a black flag during Punjab Chief Minister Bhagwant Mann's public meeting on Friday, has alleged he was beaten and tortured with electric shocks in police custody, setting off a political storm and demands for an independent investigation.

Mohanjeet Singh of Sheron village in Sangrur district was taken into preventive custody after climbing onto the roof of a house near Mann's "Lok Milni" programme and protesting over the drug problem in Punjab. A video of police personnel taking him away from the rooftop has since circulated widely.

After his release, Mohanjeet was taken to the Civil Hospital in Sangrur by family members and opposition leaders. His famil...