Meanwhile, the toll in the serial blasts rose to six after an injured person died at the Patna Medical College and Hospital (PMCH) last night.
Currently, 37 injured persons, many of them in critical condition, are being treated in the hospital.
Raids were being conducted in several areas of neighbouring Jharkhand today in connection with the blasts.
Three persons detained after the blasts yesterday were released after interrogation last night, a senior police officer said in Ranchi.
Police recovered black powder, materials used to make IEDs, pressure cooker and extremist literature during the raids, he said.
