Four people were killed and another injured when a tower crane collapsed in Harbin, northeast China\'s Heilongjiang Province, on Sunday morning, local work safety authorities said. The accident occurred around 6:50 a.m. at a construction site in Nangang District, Xinhua quoted sources with the city\'s work safety bureau as saying. The injured had been sent to a nearby hospital, the sources said. The condition of the injured is not immediately known. An investigation into the cause of the accident is under way.