Four Kenyan police officers have been charged with murder in the killings of a human rights lawyer, his client and a taxi driver that caused an uproar across the country.

The four officers were charged Monday in the high court in the capital, Nairobi.

The suspects were identified in court documents as Fredrick Leliman, Leonard Mwangi Maina, Stephen Cheburet Morogo and Silvia Wanjiku Wanjohi.

The killings of lawyer Willie Kimani, his client Josephat Mwenda and their driver Joseph Muiruri have caused protests over alleged extrajudicial killings by the police. Their bodies were pulled out of a river after they were abducted on June 23.

Kenya's police force is the most corrupt institution in the country, according to the global anti-corruption coalition Transparency International.