"A team of five to six senior officials comprising an Inspector General-level officer have reached Srinagar and will take over the probe from the J&K Police," an NIA source told .
The source said that the team will first understand all the angles of the case and then bring Singh to the agency's headquarters in New Delhi for questioning.
The source said that the NIA will try to understand when and how Singh got in touch with the Hizbul Mujahideen terrorist group, adding that during initial questioning by the Srinagar-based NIA team, Singh has confessed to supporting the terrorists for last four-five days and also hinted about the involvement of many other police officers.
Based on the investigation so far carried out by the Special Investigation Team (SIT) and the initial questioning by the NIA, the anti-terror probe agency will widen its probe into the case.
The source said that the NIA will also look at the files of the 2001 Parliament attack, which was believed to have been masterminded by a non-local Lashkar-e-Taiba (LeT) "commander" named Gazi Baba.
Singh was part of the special anti-militancy Special Operations Group (SOG) in 2002 and was named by Parliament attack convict Afzal Guru, in a letter to his lawyer, where he also suggested that another Parliament attacker Mohammad was taken to Delhi on the directions of the police officer.
The source said the agency was also tracking the DSP's property details and is set to collect the details of his bank accounts.
Singh was arrested on January 11 with top Hizbul Mujahideen commander Naveed Babu and lawyer Irfan when their car was intercepted by the police on the Srinagar-Jammu highway. According to the J&K Police, Singh was taking Babu and his accomplice to Jammu.
As per J&K Police sources, a sum of Rs 12 lakh may have been given to Singh to move the two Hizbul militants to Jammu on their way to Chandigarh and onward to Delhi to carry out attacks on or before the Republic Day.
Singh, who was posted in the anti-hijacking squad at the Srinagar international airport, was suspended from service on Monday and is likely to be stripped of all his awards, including a gallantry medal for anti-militancy operations presented on August 15 last year.
(Anand Singh can be contacted at anand.s@.in)
( With inputs from IANS )