LAHORE - A private security guard was found shot dead at a market in Nishtar Colony, police said on Saturday. The body was moved to the morgue for autopsy.   A police official said the man, identified as Ahsan, shot himself in the head with his rifle due to unknown reasons and died on the spot. He said the police were treating the incident as suicide. Further investigation was underway.  Meanwhile, two labourers wounded critically as they fell from the rooftop of an under construction house in Sabzazar on early Sunday. Rescue workers said 40-year-old Barkat and 50-year-old Zaheer Abbas were rushed to a hospital with multiple injuries.