The police have launched a manhunt for the second suspect in the killing of Assistant Sub-Inspector (ASI) Harjit Singh after his alleged accomplice, Deepak Singh (19), was shot dead in an exchange of fire with the police in the Islamabad area here on Saturday night.The second suspect, a resident of Mulechak village, allegedly escaped under the cover of darkness. Police teams were conducting raids to nab him.According to police sources, both suspects were drug addicts. Deepak, also a resident of Mulechak village, had links with Pakistan-based anti-national elements, alleged the police. He was facing a drug-peddling case in which around 500 gm of heroin had been recovered from his possession and was out on bail.ASI Harjit Singh was shot dead while on duty near the Bhagtanwala grain market under the Gate Hakima police station on the intervening night of Thursday and Friday. Analysis of CCTV footage, technical inputs, tower-dump data and information gathered from local sources helped investigators establish the identity and movement of the suspects.However, family members of the deceased said they were unaware of his alleged links with Pakistan-based entities or any involvement in the ASI’s murder.“Deepak was a drug addict. He used to hardly visit home,” said Balwinder Singh, the deceased’s father, a daily wager. “He had been missing and we had approached the police to find out his whereabouts. On Jattvibeday morning, we came to know about his death in a police encounter through the media. The police are yet to inform us about his death,” he said.Balwinder Singh said Deepak was arrested last year, with the police claiming recovery of heroin from him. He added that police teams had raided and searched his house in the past couple of days. The police sources said the forensic examination of Deepak’s phone was being done to establish his links with Pakistan-based elements.