The Bihar police on Tuesday said they were investigating the possible involvement of Pakistan’s Inter-Service Intelligence in the derailment of Patna-Indore Express in Kanpur in November, The Indian Express reported. The Anti-Terrorism Squad has been brought on board to look into the case, according to ANI.

Officials said the Pakistan angle surfaced after three suspects – Umashankar Patel, Motilal Paswan and Mukesh Yadav – were arrested from Motihari at the Indo-Nepal border. The police believe that the three accused were responsible for the Kanpur train derailment.

“These criminals were arrested for their involvement in placing a cooker bomb on the railway track near Bihar’s Ghorasahan on October 1 last year. They have confessed to having worked for a Nepal-based ISI agent [Brij Kishore Giri],” District Superintendent of Police Jitender Rana told The Times of India.

Rana said the National Investigation Agency would take over the case if the police proved the ISI link. The accused told investigators that they were given Rs 3 lakh to plant explosives on the Ghorasahan railway track. “The Nepal police have shared vital information about their ISI links,” Rana said.