Officials of the terror probe agency have also found similarities in the recent attack on the Pathankot Air Force station and a police station and some other targets in Dinanagar, both in Punjab, a Home Ministry spokesperson said.
Three heavily-armed militants in army fatigues, believed to have infiltrated from Pakistan, had on July 27 last year sprayed a moving bus with bullets and stormed a police station in Dinanagar, killing eight people, including a Superintendent of Police before being killed in a counteroffensive. The case is being probed by the Punjab Police.
NIA officials questioned Singh, who is allegedly frequently changing his statements, for the fourth straight day today.
Singh's cook Madan Gopal, who was also abducted with him and a jeweller friend of the officer, and Somraj, caretaker of Panj Peer Dargah in Punjab, were also questioned, the spokesperson said, adding they all may be confronted with each other to ascertain the veracity of their statements.
The shrine is located a few kilometres from Bamiyal, the village from where the terrorists were suspected to have infiltrated into India before mounting the attack.