A worker of Dhaka Water Supply and Sewerage Authority (DWASA) was killed and three others injured when the truck hit them early on Tuesday.The truck crashed them under its wheels where they were doing water pipeline installation work in front of Dhaka Udyan Housing Project at Mohammadpur in the capital.The injured were rushed to Dhaka Medical College HospitalFiroz Ahmed, officer-in-charge of Mohammadpur Police Station confirmed the matter to the journalists.