A man was killed and three others sustained serious injuries when roof of a workshop caved in near Liaqatpur, here on Saturday. According to police, some people were working at an auto-mobile workshop when its roof collapsed due to overburden. As a result, security guard Adnan died on the spot while Muhammad Aleem, driver Saeed and workshop owner Muhammad Latif suffered critical injuries. The injured were admitted to the THQ hospital Liaqatpur in precarious condition.