New Delhi, Jan 14 (PTI) An SP-rank officer of Punjab Police Salwinder Singh was quizzed for the fourth day today by NIA whose interrogators also questioned his cook and the caretaker of 'Panj Peer Dargah', which the official had claimed to have visited before he was kidnapped by terrorists involved in Pathankot attack.

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.

State's Deputy Chief Minister Sukhbir Singh Badal had recently refused to hand over the case to NIA, which is probing the Pathankot attack.

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.

Six terrorists had attacked the Pathankot base on the intervening night of January 1 and 2. They were killed in a counter-operation by Indian forces that lasted for about three days and also claimed the lives of seven security personnel.