The National Investigation Agency (NIA) on Tuesday confirmed that Dubai-based Shamshul Huda, who acted as "mastermind" for an ISI-backed plot to cause train accidents in India, was arrested by police in Nepal.

"Shamshul Huda has been arrested by the Nepal Police after being deported from Dubai," a senior NIA official told IANS on the condition of anonymity.

The official also described Huda's arrest as a big breakthrough in the three cases that was handed over to the agency.

The three cases comprised a failed attempt to detonate an IED (Improvised Explosive Device) on the Ghorasahan track in East Champaran district of Bihar on October 1, 2016; the suspected sabotage behind the Indore-Patna Express train accident in Kanpur on November 20, 2016, that killed 149 people; and derailment of Hirakhand Express in Koneru in Andhra Pradesh on January 21 which resulted in the deaths of 41 persons.

The NIA official further said that the agency was in touch with the Nepalese authority to seek access to Huda for questioning.

Pakistan's Inter-Services Intelligence (ISI) agent Huda, was also a known operative of fake Indian currency and has a network in Nepal.

After the Home Ministry's January 25 and 26 orders, the NIA took over the Ghorasahan, Kanpur and Koneru cases to probe ISI's role, which was first pointed out by the Bihar police.

In January, Bihar police arrested three criminals from Motihari -- Moti Paswan, Uma Shankar Patel and Mukesh Yadav -- and informed central agencies about their links with ISI agent Huda and the Ghorasahan and the Kanpur incidents.

"Technical evidences and the initial questioning of three arrested criminals by Bihar police have led NIA to probe ISI's role in two train accidents and a failed attempt of track blast in India on various occasions.

"WhatsApp chat details and other technical evidences has indicated clear link among the arrested criminals, Nepalese handler Brajesh Giri, Dubai-based mastermind ' title=' mastermind '>mastermind Shamshul Huda as well as a Karachi-based suspected ISI agent Shafi Shaikh. All these inputs are enough to confirm the ISI role," a Home Ministry official said.

Initial investigations reveal that Giri had given Rs three lakh to the arrested criminals for planting a bomb on the rail tracks at Ghorasahan.

Investigators said that Umashankar Patel, one of the accused, came in touch with Shamshul Huda and Shafi Shaikh during a telephonic conversation organised by Giri when the two masterminds were together in Dubai around seven month ago