The home ministry's high-level investigation committee and also the officers investigating the murder of retired major Sinha Md Rashed Khan, visited the Teknaf Police Station multiple times in a bid to collect CCTV footage for the sake of investigation.
But no footage from that night has been recovered so far as those have been erased without a trace. Only the then officer-in-charge (OC) Pradeep Kumar Das had full access to and complete control of the CCTV system at that police station.
Responding to a query on condition of anonymity, a member of the home ministry's investigation committee said, "We tried to collect the footage of that night to determine whether OC Pradeep went to the scene of the incident from the police station or from somewhere else.
"We found two CCTV cameras at the station, which could only be operated from the OC's room. But we could not recover any footage recorded between July 25 and August 6."
According to sources, the home ministry's probe body and also the investigation officer of the Sinha murder case later wrote to the Police Headquarters regarding the CCTV footage from the Teknaf Police Station.
The Police Headquarters then sent an ICT expert team to assess the situation. The team informed the Police Headquarters that it found two CCTV cameras in working condition at the police station, but found no trace of the recorded footage.
The expert team further learned that one of the CCTVs has no hard disc, and the other has a one terabyte hard disc. Both the CCTVs were operated from the OC's room at the station and he had full control of the hard discs too.
The team also found evidence that someone has erased all the footage from the hard disc recorded between July 25 and August 6.
On August 6, the suspended OC Pradeep, along with six other policemen, "surrendered" before the Cox's Bazar court.
"The ICT team also pointed out that only the OC had control of the hard disc and no one else could have erased the footage without his consent," a source told The Business Standard.
Meanwhile, a probe body member said, "The CCTV footage of that night when Sinha was killed is very important for the investigation. Eyewitnesses said they had seen OC Pradeep on the spot of Shamlapur only 10-12 minutes after the killing, but the Teknaf Police Station is at least 25-30 minutes away from the spot.
"We need the footage of that police station to investigate whether it was a pre-planned murder or not."
Meanwhile, the Rapid Action Battalion (RAB) has tracked down 29 electronic devices belonging to Sinha and Shipra Debnath.
The Ramu Police Station made the seizure list of Sinha's laptop, camera, hard disc and other electronic devices of Sipra Debnath and Sifat around five days after the drive to the Nilima Resort, which took place on August 6.
RAB sources said the Ramu police made the seizure list of these devices in connection with another case, instead of the case filed over Sinha's murder."
When asked, ABM Masud Hossain, superintendent of police of Cox's Bazar declined to make any comment regarding the matter.
The RAB Legal and Media Wing Director Lt Col Ashique Billah told the media that they have received the electronic devices as case documents as per the court's permission. "We will send those devices for forensic tests to investigate the case thoroughly," he added.