Dipa Bhowmik was present in court on Tuesday when District and Sessions Judge ABM Nizamul Haque announced her verdict.
More than a hundred lawyers from the Rangpur Bar Association were in the courtroom when police produced Dipa in handcuffs before the judge.
On Mar 30 last year, Rathis went missing after leaving his home at Babupara on his motorcycle with another person in the morning, his family had said.
The Rapid Action Battalion then arrested Tajhat High School teacher Dipa and her two colleagues, Kamrul Islam and Motiar Rahman.
Following their arrest, Rathir’s body was found buried under sand in a construction site for a building owned by Kamrul’s brother on Apr 3.
Police then filed charges in court against Dipa and Kamrul, saying the two killed Rathir so they can get married. Both were teachers at Tajhat High School.
Kamrul, who had been ill from diabetes and heart disease, died in jail on Nov 10, according to authorities.
Rathish was a special public prosecutor in the murder trial of Japan national Hoshio Kuni, law secretary of the ruling Awami League’s Rangpur District Committee, president of the district unit of Bangladesh Puja Udjapon Parishad, a trustee of the Hindu Welfare Trust and general secretary of Sammilita Sangskritik Jote in Rangpur.
The couple had two children, a son and a daughter. The son is a law student while the daughter is studying at night grade.