SILIVRI, Turkey — Lawyers for philanthropist Osman Kavala, held in solitary confinement for nearly two years on charges he financed anti-government protests, may skip future hearings in protest, exasperated with what they call a disregard for the law in a politically motivated case.

A court on Tuesday refused to release Kavala, who is spending his 708th day in prison, citing the seriousness of the alleged offenses and his potential flight risk. He is the only suspect in the case imprisoned during the trial, despite facing the same grave allegations as his 15 co-defendants. They face life in prison if convicted on charges of terrorism and seeking the violent overthrow of the government.

Kavala is now set to spend at least another 10 weeks in prison because the court adjourned until Dec. 24. At the hearing, he and eight other defendants were questioned about their efforts in 2013 to save a public park in central Istanbul that mushroomed into the largest anti-government protests in a generation, with 3.5 million people protesting in 80 of Turkey’s 81 provinces. The defendants, who include a filmmaker, educator, architect and city planner, deny the charges, arguing that the spontaneous eruption of anger was too large for any of them to start or stop.

Members of the three-judge panel have been replaced repeatedly, with justices who have expressed the dissenting view to release Kavala removed from the case. The 657-page indictment is based largely on what lawyers said were unlawfully obtained wiretaps of phone calls.