The last time Bangladesh University of Engineering and Technology (Buet) student Fardin Noor Parash was tracked down was in Gazipur, said Home Minister Asaduzzaman Khan.
"How Fardin's body ended up in Shitalakhkhya river is being investigated," he told reporters at Rajarbagh Police Lines in Dhaka on Thursday, according to UNB.
He said investigation is underway, treating it as a murder.
It will be possible to share details after the investigation is complete and report is received, he added.
Those behind Fardin's death will be brought to justice after identifying them, he said.
Fardin, a third year student of Buet's civil engineering department, and a resident of Qutubpur area in Narayanganj's Fatullah, was found dead in the Shitalakhkhya River on November 7, three days after he went missing.
Earlier on Thursday, police arrested Fardin's friend Amatullah Bushra, third year student of a private university, from her Banasree home in Dhaka after Fardin's father filed a case against her and some unidentified people with Rampura Police Station.
The Detective Branch of police has taken charge of investigating the murder.
DB chief Harunor Rashid confirmed the development at a media briefing on Thursday as police were granted five days to grill in custody Amatullah Bushra, a friend of Fardin.
