Ten key points top the NIA's agenda as it probes the audacious terrorist attack on the IAF base at Pathankot in Punjab that has caused fresh strains in India - Pakistan relations.
The National Investigation Agency, which took over the case on January 4 from Punjab Police, is to uncover the sequence of events from the time the terrorists, believed to be Pakistanis, sneaked into India to the attack.
Some 36 hours of fighting at the base left seven security personnel dead. All six terrorists were also killed.
The key points the NIA is investigating include mobile phone conversations between the terrorists and their suspected handlers in Pakistan, a Jaish - e - Muhammad letter, DNA samples of the terrorists, and their voice record samples.
Other issues being focussed on include ammunition the terrorists carried, their strategy, suspected involvement of locals, the route the terrorists took from the India - Pakistan border, the accounts given by a Punjab Police officer, his friend and cook after their abduction by the terrorists just before the attack, and a Pathankot map found from the police officer's car, an NIA officer told IANS.
"A 20 - member team of NIA, led by an inspector general, has been camping in Pathankot to supervise the investigation. Our focus is on the key points, " the officer told IANS.
An officer of the rank of superintendent of police has been appointed the chief investigating officer of the case, he said.
The NIA took over the case by filing three separate First Information Reports (FIRs).
These were filed in connection with the abduction of Gurdaspur Superintendent of Police Salwinder Singh, along with his jeweller friend and cook, the earlier killing of taxi driver Ikagar Singh, and the terrorist strike at the Indian Air Force station.
Another NIA officer told IANS that the lapses by the Border Security Force (BSF) in preventing the infiltration from Pakistan into Bamiyal sector adjoining Gurdaspur in Punjab and Kathua in Jammu and Kashmir were being investigated at the highest level.
The failure of Punjab Police, which looks after the security of areas near the border, was also under the scanner, the NIA source said.
The NIA is also trying to establish the identity of local residents who provided army fatigues and a walkie - talkie to the six terrorists after they infiltrated into Punjab, possibly on December 30.
The NIA officer said the DNA samples of the terrorists have been sent to Pakistan for establishing their identity. Voice samples of the terrorists have also been sought from Pakistan.
The statements of the police officer, his friend Rajesh Verma and cook Madan Gopal were being thoroughly analysed, the officer told IANS. All of them will soon face lie detector tests.
The statement of the officer's personal security officer, Kulwinder Singh, has also been taken.
The officer said the calls made from the mobile phone of the abducted victims were being analysed along with the number belonging to the dead Innova driver, Ikagar Singh.
The NIA team on Wednesday took police officer Salwinder Singh to the place near Kolian village, 25 km from Pathankot, from where he was allegedly abducted in his car along with the two others. The NIA team also took the officer to the place where he was dumped by the terrorists and to the spot where his car was found abandoned.
The NIA team is looking at what the officer did for nearly three hours after he and the others allegedly left a shrine in Kathua district at 9. 30 pm on December 31 - - till they were allegedly abducted on the midnight of January 1.
The superintendent, who was transferred from Gurdaspur last week, had claimed that he, along with Verma and the cook, were stopped and abducted by four or five heavily armed terrorists near Kolia village.
He claimed that his senior officers did not initially take his information on the presence of terrorists seriously.
(Rajnish Singh can be contacted at rajnish. s@ians. in)