THIRUVANANTHAPURAM: The National Investigation Agency (NIA) is set to take over the investigation after a week has passed since the train fire incident, in which Delhi teenager Shahrukh Saifi was detained. Even after taking 24-year-old Saifi into custody on Friday (April 7), the SIT team led by top Kerala ADGP M.R. Ajithkumar is still questioning him, said sources. It doesn't appear that much progress has been made. It should be emphasized that the Center seems dissatisfied with the continuing SIT investigation. The Kerala Police was criticised by Union Minister V. Muraleedharan for its "inefficiency" and claimed that the only action taken by the force following the incident on April 2 was to drive the offender back to the state, and that too without making adequate security arrangements from Ratnagiri in Maharashtra. On April 2 night, Saifi set a few passengers on fire by dousing them in petrol while the train was moving. She then boarded another train from Kannur and debarked in Ratnagiri a short time later. 3 people, including a 2-year-old girl, died after they panicked and jumped out of the moving train. 9 others suffered burn injuries. Meanwhile, Saifi has informed the SIT that neither he nor anyone else saw anyone leap out of the train or push someone out of it. The SIT has so far been successful in locating the petrol station where Saifi bought petrol in the Palakkad district of Kerala, in Shornur. He spent several hours at Shornur before boarding the train. It should be underlined that the central agencies have been on high alert ever since the tragedy, and it was their efforts that enabled a squad from the Maharashtra Police's Anti-Terror Unit to apprehend Saif in Ratnagiri. As the Kerala Police have not yet filed any charges in accordance with the UAPA, all eyes are on the NIA's next move. Kerala train attack: Shahrukh Saifi brought to Kozhikode Kerala Cabinet forms Spl authority for Munnar Hill Area Dev Kerala Train Fire: Railway Minister thanks Maha Govt for nabbing suspect