The blast on the Patna-Delhi Shramjivi Express train last year was carried out by the banned Bangladeshi group Harkat-ul-Jehadi Islamia, police said in Jaunpur on Wednesday.
The main accused in the case -- Obaid-ur-Rehman who has been remanded to police custody till May 22 -- has told the police that the bomb was planted at the Patna station by terrorists, Superintendent of Police Sanjiv Gupta said.
Gupta said Obaid-ur-Rehman was a resident of the area under Kaliyani police station of Sherupur district in Bangladesh and was associated with the outlawed group.
Before his arrest, Obaid-ur-Rehman had never been to Uttar Pradesh, he said.
On July 27 last year, 12 people were killed instantly by the blast on the Delhi-bound train. Several others were wounded in the attack, and five of them later succumbed to their injuries.