Surat Ikramov told RFE/RL's Uzbek Service security that officers met with defendant Dadakhon Hasan and promised him he would get a shorter sentence if he rejected his lawyer.
"[Hasanov] called at around 18:00 [on August 11] and told me two high-ranking officers from the Interior Ministry's Antiterrorism and Antireligious Extremism Department sent him a driver and asked him to come [to an agreed location]," Ikramov said. "The conversation ran about me. They told Dadakhon that he should refuse my help and that my participation in his trial should stop. In exchange, they promised his sentence would be [reduced, or] commuted."
Ikramov heads the Tashkent-based Initiative Group of Independent Rights Defenders.
The 66-year-old Hasan is charged with insulting President Islam Karimov, anticonstitutional activities, and preparing and distributing material that threatens public security.
His trial started on July 31. It was adjourned several times and resumed earlier this month.
Uzbek officials say 187 people -- including many security officers -- died during last year's antigovernment uprising in Andijon.
But rights groups say government troops killed hundreds of unarmed civilians.
The song Hasan wrote after the events refers to Andijon being "drowned in blood" and victims "falling like mulberries."
(RFE/RL's Uzbek Service)