The agency has got transit remand of the alleged operative, identified as Mohammed Danish Ansari, son of Mohammed Zafeer Ansari and resident of Chakjora village (under Laheriasarai police station area) in Darbhanga, who was arrested by its sleuths last night.
Official sources said a non-bailable warrant had been issued against him by a special National Investigation Agency (NIA) court in Delhi last year.
They claimed that security agencies were trailing Ansari , who allegedly provided shelter to Bhatkal, who is supposed to be hiding in Pakistan.
Danish Ansari was also wanted by the Delhi Police in a terror-related case it is probing, sources claimed.