Superintendent of Police Amit P Javalgi said one person Chandan Roy has been arrested in connection with the blast from Moynaguri area of Jalpaiguri district.
The SP said some persons have also been detained in connection with the bicycle bomb blast and police was questioning them to find out their role in the blast.
"Investigations into the blast case are going on in the right direction and we are taking the help of all agencies to crack the case," Javalgi said.
Asked whether the Kamtapur Liberation Organisation (KLO) was responsible for Thursday's bicycle bomb blast, the SP refused to comment.
The SP alongwith District Magistrate Pritha Sarkar announced that prohibitory orders under section 144 CrPC would be in force in some places of the district headquarters town of Jalpaiguri in view of procession of some political parties.
An alert has been sounded across the district and patrolling has been intensified in the border areas of the district, which is adjacent to Bangladesh, Bhutan and Nepal.
A blast in a moving bicycle on Thursday killed six persons near Bajrapara area on Thursday. The attack was suspected to have been carried out by extremist outfit Kamtapur Liberation Organisation (KLO).
Formed in 1993, the KLO has been fighting for a separate Kamtapuri state comprising six districts of north Bengal and some areas of Lower Assam.