The convicts are – former Jatiya Party (JaPa) MP Abdul Quader Khan, Mehedi Hasan, Shahin Mia, Anwarul Islam, Abdul Mannan, Shamsuzzoha and Chandan Kumar.
Another accused, Subol Chandra Das, died in prison.
District and Sessions Judge Dilip Kumar Bhowmik pronounced the verdict after examining records and witnesses.
Liton, a former MP from Gaibandha-1 constituency, was gunned down by miscreants at his village home in Masterpara of Sundarganj upazila on December 31, 2016.
Liton’s sister filed a case against several people at the Sundarganj Police Station.
Detectives arrested Quader, a former Jatiya Party MP from Gaibandha-1 constituency, on February 21, 2017 from his home. Five days later, he confessed before a court to his involvement in the killing.
On April 30, 2017, police submitted a charge-sheet against eight people, including Quader who had previously been sentenced to life imprisonment in a separate case filed under the Arms Act.