The National Investigation Agency (NIA) on Tuesday confirmed that Dubai-based Shamsul Huda, who acted as the alleged mastermind for the ISI-backed plot to cause train accidents in the country, was arrested by the police in Nepal."Shamshul Huda has been arrested by the Nepal Police after being deported from Dubai," a senior National Investigation Agency (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; the suspected sabotage behind the Indore-Patna Express train accident in Kanpur on November 20, 2016, that killed 149 people; and the derailement 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 is in touch with the Nepalese authority to seek access for his questioning.