Md Helal Uddin, judicial magistrate of Cox’s Bazar, passed the order when members of Rapid Action Battalion (Rab) produced the accused before his court with remand plea.
Plaintiff’s lawyer Md Mustafa said the court put the three on a seven-day remand while the rest will be interrogated at the jail gate.
All nine accused were produced before the court around 5pm and Judge Md Helal initially ordered to imprison them. Later, the court heard a remand plea by Rab and granted investigators seven days to interrogate the suspects.
Major (retd) Sinha was killed in police firing at Baharchhara police check-post on July 31.
Later, two people were arrested and two cases were filed over the incident, Superintendent of Police ABM Masud Hossain said Saturday.
Sharmin Shahriar Ferdous, elder sister of Sinha, filed the case at Teknaf Senior Judicial Magistrate Court on Wednesday.
The other accused are Sub-Inspector Nandalal Rakshit, Assistant Sub-Inspector Liton Mia, Tutul, constables Safanur Karim, Kamal Hossain, Abdullah Al Mamun, and Mohammad Mostafa.
Senior Judicial Magistrate Tamanna Farah issued arrest warrants against all of the accused after taking the case into cognizance on Wednesday.
OC Pradeep surrendered on Thursday noon and later police took him to Cox’s Bazar.
Also read: Major Sinha killing: Arrest warrants issued against 9 policemen
The Home Ministry formed a four-member committee, headed by Mizanur Rahman, additional divisional commissioner (development), on August 2.
The authorities on Sunday suspended 21 police officials, including the in-charge of Baharchhara police outpost, in connection with the killing.
Also read: 21 cops suspended over killing of ex-Army major in Teknaf
Prime Minister Sheikh Hasina on Tuesday assured the mother of Major Sinha of proper investigation into the murder of her son and the trial of his killers.
Also read: PM assures ex-Major Sinha's mother of fair trial of his murder