A military court in the Democratic Republic of Congo has sentenced four police officers to death for the murder of an influential human rights activist.

The court sentenced another police officer to life in prison for the death of Floribert Chebeya.

Chebeya headed one of Congo's most prominent human rights organizations – Voice of the Voiceless.

His body was found in the back of his car on the outskirts of Kinshasa in June of last year. Chebeya had been summoned to meet with Congo's head of police, General John Numbi, shortly before his body was found.

One of those sentenced to death on Thursday was Numbi's second-in-command, Colonel Daniel Mukalay.

Chebeya had been arrested by Congolese authorities multiple times in the previous two decades and had expressed fear he was being watched by security forces.

Chebeya's driver, Fidele Bazana, disappeared at the time the activist's body was found. He remains missing.

The case sparked an outcry by international rights groups which demanded an independent investigation be conducted and that those responsible for the death be held accountable.

The United Nations and United States also expressed concern. U.N. human rights official Philip Alston suggested the Congolese government was “very likely” involved in Chebeya's death.