KOLKATA: The West Bengal Criminal Investigation Department (CID) has taken over an ongoing probe into last week's Nagerbazar explosion that left a boy dead and nine others injured. A case has already been registered against unknown persons in connection with the case. DIG CID (Operations) Nishant Pervez said, “We have taken over the investigations into the Dum Dum Nagerbazar explosion case. Our officers will soon reach the spot to carry out the probe.” He said samples have been collected from the spot and forensic tests are being conducted to ascertain what type of material was used in the blast in Nagerbazar. “We have started a suo motu case against unknown persons in this case. Strict actions will be taken as per law against those found guilty,” he said.