"The investigation is building up on some suspects, but we can't reveal anything at this stage," said a senior police officer.
He was asked about reports that the National Investigation Agency was looking for a girl student from Bokaro in connection with the serial blasts in Patna and Bodhgaya.
NIA has arrested one person here on October 30.
Earlier on October 27, one Ujjair Ahmad was arrested in Ranchi after one Imitiaz Ansari was caught in Patna.
The NIA, which is simultaneously working on the Bodhgaya blasts that had left five injured in July this year, is being actively assisted by Jharkhand Police in raids in various places, the officer said.
They raided Chakla village on the outskirts of Ranchi yesterday to trace a person in whose name a room was booked in a lodge at Hindpiri here, where police recovered nine timer-fitted bombs, detonators and gelatin on Monday, police said.