NEW DELHI (AP) — An Indian court sentenced a university professor and four others to life imprisonment on Tuesday on charges of belonging to a banned communist rebel group and recruiting others to join them.

Judge S.S. Shinde found them guilty in Gadchiroli, a town in western Maharashtra state.

The professor, G.N. Saibaba, taught English at a New Delhi college. He was arrested in 2014 and accused of being a member of the banned Communist Party of India (Maoist), but denied any involvement.

Saibaba is paralyzed from the waist down and uses a wheelchair.

Police said they arrested Saibaba after a defendant told them he was acting as a courier between Saibaba and Maoist insurgents operating from forests in western Chhattisgarh state.

The five can appeal the verdict.

The Maoist rebels, who claim inspiration from Chinese revolutionary leader Mao Zedong, have been fighting the Indian government for more than four decades, demanding land and jobs for tenant farmers and the poor.

The Indian government has called the rebels India's biggest internal security threat. They operate in 20 of India's 28 states and have thousands of fighters, according to the Home Ministry.