Chennai: A 24-year-old construction supervisor from Bihar was robbed of ₹3,000 in cash and his mobile phone after two unidentified men lured him into an auto-rickshaw on the pretext of helping him book a train ticket near Perambur railway station in Chennai on Friday.The suspects took him to a secluded area in Sembium, threatened him with a knife, robbed him and fled. The Thiru Vi Ka Nagar police registered a case.The victim, Ashok Kumar, 24, a native of Bihar, lived in Nungambakkam and worked as a construction supervisor in the city.Ashok Kumar arrived at Perambur railway station on Friday evening to travel to his hometown in Bihar. While he was waiting for his train, two unidentified men approached him, struck up a conversation and offered to help him book a train ticket. Trusting them, Ashok Kumar accompanied the men in an auto-rickshaw. The suspects diverted the vehicle to a secluded location in Sembium, where they robbed him of cash and his mobile phone at knife-point.On his complaint, the Thiru Vi Ka Nagar police registered a case, secured the CCTV footage in the vicinity and launched a manhunt to trace the suspects.