Three air-conditioner mechanics were found dead and a fourth was rescued in an unconscious state from a locked rented room in south Delhi’s Dakshinpuri neighbourhood on Saturday, Delhi Police said. Officers received a control-room call at about 11:15 a.m. from Zishan, a relative who could not reach the men by phone and discovered the door bolted from inside. Police identified the deceased as brothers Imran alias Salman and Mohsin and an as-yet-unidentified colleague. The survivor, Haseeb, is undergoing treatment at Safdarjung Hospital. All four men shared the first-floor room while working in the capital as AC mechanics. Investigators suspect the men died of suffocation, possibly caused by a leak from a gas cylinder kept in the room, which lacked ventilation. A forensic team has inspected the premises, and post-mortem examinations will determine the exact cause of death. Statements from neighbours and relatives are being recorded as part of the continuing probe.