Shahedul Islam Sifat, who had been accompanying retired army Major Sinha Mohammad Rashed Khan on last Friday night from Teknaf to Cox's Bazar, claimed Sinha's murder looked like it was pre-meditated.
The private university student said the police inspector who shot Sinha was talking over his mobile phone and seemed to be carrying out the command he received from the other side during the firing.
"While talking over the phone, he addressed the other side as 'sir' and also replied, 'Okay sir, I am doing it'. Then he shot Sinha," Sifat told the home ministry probe body on Tuesday as the team visited him at Cox's Bazar jail.
A source closely involved in the quizzing of Sifat inside the jail told The Business Standard that the student also claimed that the former army officer neither tried to pull out his licensed firearms, nor retaliated even after being shot.
He categorically discarded the police version of the incident, as police said they had to open fire in self-defense.
The probe body also talked to Shipra Debnath, another teammate of Sinha and also a private university student, at the prison. Police have accused the duo in two separate cases on charges of attempted murder and carrying narcotics.
Major (retd) Sinha had been in Cox's Bazar with the students for making a documentary film.
Recalling the night Sifat told the probe body, "It was around 9:25 pm Friday and we were returning from the shooting spot in Baharchara union of Teknaf upazila in Cox's Bazar. We crossed two different checkpoints of Armed Police Battalion and Border Guard Bangladesh and everything was fine."
Sifat said police then signaled them to stop at Shamlapur checkpoint on Cox's Bazar Marine Drive -- the third check-post they faced that night.
The student said, "Sinha sir pulled over the car. The police camp Inspector Liakat Ali then shouted to put our hands up and we did so. Sinha sir got off the car while I was sitting in front of the vehicle.
"He gave his identity and told the policemen that he was a former major of the Bangladesh Army. He even offered the policemen to verify the identity by calling the concerned authorities," added Sifat.
"But Liakat opened fire on him without any warning," Sifat claimed.
"After shooting, Liakat also pressed Sinha sir's throat with his boots as he was groaning in pain. The on-duty police then tried me and asked about our identity," he said.
'Narco recovery also a made-up story'
Sifat told the investigation team that they neither were drunk nor carrying any narcotics at that night.
"We know the place for at least 28 days. Then why would we risk the journey even after knowing that the Marine Drive has multiple check-posts," he told the probe committee.
He also said police's claim about the local villagers shouting assuming them robbers was also a lie.
"We met two or three locals on our way back from Teknaf and they asked about our identity. But they never shouted assuming us robbers," he told the probe body.
Shipra Debnath, another teammate of Sinha, was at a local resort on Friday night. She told the probe body that she had been with the documentary team since July 3 and she never saw the former army official angry or agitated.
Echoing her, the resort owner Monzurul Kabir said that Sinha was a generous and humble person in his entire stay.
"Even I did not see him talking loudly with anyone. How could he point a gun at police," he wondered.
Shahjahan Ali, additional district magistrate of Cox's Bazar and also coordinator of the probe body, said they will submit the report immediately.
On Friday night, Major (Retd) Sinha was killed in police firing on Cox's Bazar's Marine Drive.