Koraput: Koraput police on Friday seized around 128.3 kg of ganja concealed in a specially-built secret chamber of a goods vehicle near Tangini Chhak in Sunki Ghati under Sunki police limits. The cannabis was concealed in several packets, said SP (Koraput) Rohit Verma. The driver and helper of the vehicle were detained. The seizure and subsequent proceedings were conducted in the presence of Pottangi tehsildar-cum-executive magistrate Debendra Dharua. Police sources said probe is on to establish the source of the consignment, its intended destination and the network involved in its transportation.