Days before Maj (retd) Sinha Rashed Khan was murdered on July 31, then officer-in-charge of Teknaf Police Station Pradeep Kumar Das had threatened to "destroy" him unless he left the area.
"While filming for his YouTube channel, Sinha independently looked into drug trade in Teknaf and found its links with Pradeep," Lt Col Ashiq Billah, director of Rab's legal and media wing, told a press conference yesterday.
"Sinha was a friendly person and people opened up to him, telling him how the OC oppressed and used them for the drug trade. Upon finding such allegations, he went to meet Pradeep at the Teknaf Police Station in mid-July," he said.
Billah was addressing the press conference at the Rab's media centre in the capital after investigators pressed charges against 15 accused, including Pradeep and Baharchhara Investigation Centre's Inspector Liaqat Ali, for the murder.
"Pradeep told Sinha to leave the area and threatened to destroy him if he did not do so," he said.
Talking to The Daily Star later, a highly-placed Rab source said Sinha had found out that the OC had been using several Rohingyas in a cross-border yaba trade, the daily worth of which was estimated at Tk 50 lakh.
Several sources linked with the murder investigation said Sinha had volunteered to dig into the drug trade on his own, although he had taken early retirement from the army in 2018.
Pradeep became the OC of Teknaf Model Police Station on October 19, 2018. At least 87 people were killed in 48 incidents of "gunfights" involving Teknaf police alone between August 1, 2018 and August 1, 2020, according to reports of this newspaper.
"Pradeep planned to kill Sinha before he could expose anything to the higher authorities," said Billah, while addressing the press conference.
He said they came to this conclusion based on confessional statements made by 12 of the arrested accused in the murder case, and upon analysing some digital contents, which were in the possession of Sinha and his associates Shipra Debnath and Shahedul Sifat.
While talking to this correspondent, Lt Col Billah added that the electronic devices were in the possession of the police for a considerable amount of time after the murder. When Rab officials finally got hold of them, the memory cards were found to be corrupt.
The devices were under Ramu Police Station's custody from the day of the murder till August 19, when a district court ordered that they be handed to Rab.
Yesterday, Senior ASP of Rab Mohammad Khairul Islam, investigation officer (IO) of the case, submitted the charge sheet to Judge Tamanna Farah of Cox's Bazar Senior Judicial Magistrate Court-4 through the court inspector around 10:10am.
The charge sheet was filed after four months and 10 days of investigation.
"The conspiracy [of murder] was plotted by OC Pradeep, Inspector Liaqat, and local police sources Nurul Amin, Mohammad Aiyas and Nizamuddin," said Lt Col Billah.
Liaqat, SI Nandadulal Rakshit and three APBn members then executed the plan, he said. The APBn members are SI Mohammad Shahjahan and constables Md Rajib and Mohammad Abdullah.
"In addition, other policemen from a nearby camp, namely SI Liton Miah and constables Safanur Karim, Kamal Hossain Azad, Abdullah Al Mamun ensured that a wounded Sinha bled to death as they assisted in the murder," he said.
"Constables Sagar Deb and Rubel Sharma staged an act of recovering narcotics from Sinha's vehicle. Both of them are on the run," Billah said.
The charge sheet named 83 people as witnesses.
A total of 14 people were arrested between August and September in the case. Twelve of them gave confessional statements to court.
OC Pradeep and constable Rubel Sharma were yet to confess.
In addition to murder charges, the accused are being charged for hatching a criminal conspiracy, evidence tampering and perjury.
Shipra and Sifat have already been cleared of narcotics charges, which were brought against them after Sinha's murder.
Meanwhile, a Cox's Bazar court yesterday dismissed a revision petition filed by Liaqat Ali, suspended inspector of Baharchhara Investigation Centre, challenging the legality of the murder case filed by the victim's sister, Sharmen Shahria Ferdush.
After holding a full hearing on the petition, Mohammad Ismail, judge of Cox's Bazar District and Session judge's court, passed the order, our Cox's Bazar correspondent reported, quoting Public Prosecutor of the court Faridul Alam as saying.
On October 4, Liaqat Ali filed the revision petition with the Cox's Bazar court, saying the murder case was illegal.
Sinha was killed at an APBn checkpoint on the Cox's-Teknaf highway on July 31. Local police said Inspector Liaqat's team had taken over the checkpoint from the three APBn officers before the incident.
Sinha was shooting videos for his YouTube channel at the village of Marishbunia right before he was shot. He had been residing in the area for a month for filming.
The law enforcers claimed that they tried to search the vehicle of Sinha Md Rashed Khan, but the former army official aimed his pistol at them, prompting them to shoot in self-defence.
They also claimed that they found drugs in Sinha's car.
Witnesses, however, gave different accounts of the incident. They said Sinha got down from his car, put his hands over his head, and then the police members shot him.
Sinha's family termed the incident a cold-blooded murder and launched the legal battle seeking justice.
Later, the case's investigation was handed to Rab.