The authorities at the Modern Central Jail here recovered 41 grams of contraband, suspected to be heroin, following a search operation inside the prison premises. Acting on specific intelligence, jail officials conducted a thorough inspection of the barracks, leading to the recovery on Tuesday.On the complaint of Assistant Jail Superintendent Veerpal Singh, the police registered a case under relevant sections of the NDPS Act and the Prisons Act against four inmates.The accused have been identified as three undertrials—Mahakdeep Singh of Muktsar, Narinder Singh alias Nindi of Faridkot, and Jattvibeny of Guru Har Sahai—along with a convict identified as Dharamender Singh alias Lovely.According to police sources, the contraband was smuggled into the barracks, raising fresh concerns over security measures within the high-security facility. The police have launched an investigation to ascertain the exact route used to sneak the illicit material inside and to identify any external accomplices or prison staff involved. Further interrogation of the named inmates is under way.