The ship carrying the Bangladeshis will bring back Myanmar security personnel who crossed the border recently amid fighting with rebels
A team of the Detective Branch held Shah Alam in Tongi on Saturday night, said DMP Additional Deputy Commissioner Md Yusuf Ali.
Shah Alam and three others dragged ASP Mizanur inside a car for mugging but later they found out his identity and strangled him and dumped his body on the spot, according to the police.
He left his Uttara home for work around 5am that day in plainclothes. His home is 20 minutes away by car from the spot where he was found dead.
The body bore bruises on neck and other parts, Dhaka Medical College Hospital said in an autopsy report.
Rahman was posted in Savar circle of the highway police under Gazipur zone.
His younger brother Masum Talukdar started a murder case against several unnamed people with Rupnagar police.