Barjis Shabnam Barsha and her friendMahir Rahman planned the murder of Jagannath University student Jobayed Hossen about a month ago, police said yesterday.

DMP Additional Commissioner (Crime and Operations) SN Md Nazrul Islam shared the information at a press briefing at the DMP Media Centre after interrogating the two.

Earlier yesterday, Jobayed's brother, Enayet Hossain Saikat, filed a murder case with Bangshal Police Station, accusing Barsha, 19; Mahir, 19; Mahir's friend Fardin Ahmed Aylan, 20; and four to five unidentified others.

Later in the day, the three accused gave confessional statements before separate Dhaka metropolitan magistrates. They were then sent to jail.

Meanwhile, JnU students staged demonstrations on the campus, demanding justice for Jobayed's murder.

At the briefing, DMP official Nazrul said Barsha and Mahir had been in a relationship for about one and a half years. However, Bangshal police had earlier said their relationship dated back nine years.

"Barsha developed a relationship with Jobayed while he was tutoring her, even though she was already involved with Mahir," said Nazrul.

Later, Barsha told Mahir she no longer liked Jobayed. Then they planned to kill him, he added.

According to the case documents, Mahir became aware of Barsha's affair with Jobayed about a month before the murder, which led to frequent quarrels.

On Sunday afternoon, Jobayed went to Barsha's home in Armanitola for private tuition. Mahir and a friend were reportedly waiting nearby. Then Mahir confronted Jobayed and asked him to stop seeing Barsha. Jobayed reportedly refused to do so, saying she loved him. Mahir then stabbed him in the neck, police said.

"Mahir and Barsha had made several plans to kill Jobayed. Barsha used to inform Mahir when Jobayed arrived and left her house," according to case documents.

Investigators said Mahir and Aylan bought a switch-gear knife for Tk 500 from Bau Bazar in South Keraniganj's Aganagar area.

DMP Deputy Commissioner (Lalbagh Division) Mallik Ahsan Uddin Sami said, "After being stabbed, Jobayed ran upstairs seeking help, knocking on several doors, but no one opened. On the second floor, he begged Barsha for help, but she didn't assist him."

Regarding reports that Mahir's mother turned her son in, Nazrul said police applied "tactical pressure" on the family, and it was not a voluntary act. "This was part of the police's strategy," he said.

Police detained Barsha on the night of the murder. Mahir and Aylan were arrested the following day.