JHAPA: A construction worker was killed and three others were injured when an under-construction wall collapsed at Khayardandi, Mechinagar-1 of Jhapa district today. The deceased is 55-year old Subol Singh of Badariya in Bihar of India. Other injured in the incident are Biran Singh (22), Tilak Singh (19) and Nahir Alam (21) of Badariya. The injured are undergoing treatment at Birtamode based B&C Hospital.