A Nigerian court ruled the leader of a banned Nigerian Shi’ite Muslim group in custody could seek medical treatment abroad, after a series of protests calling for his release turned violent in July.

Nigeria banned the Islamic Movement in Nigeria (IMN) last month after a week of protests in which the group said at least 20 of its members were killed in police crackdowns.

The group’s leader, Ibrahim Zakzaky, has been held since 2015 when government forces killed around 350 people in a storming of its compound and a nearby mosque. He has not been released despite a court order to that effect, and the IMN said his detention is illegal.

However, on Monday a judge in the northwestern city of Kaduna granted Zakzaky and his wife permission to seek medical treatment in India under supervision of state officials.

Zakzaky’s lawyers have said that while in detention, Zakzaky lost an eye to advanced glaucoma and risks losing the other, while shrapnel lodged in his body since the 2015 storming of the IMN compound was causing lead poisoning.

The government says IMN incites violence, and a court has given the authorities permission to label it a terrorist organization.

IMN denies it is violent and says Zakzaky should be set free as per the December 2016 court directive.