Kenyan prosecutors said on Monday they approved murder charges against six people, including three police officers, for their role in killing a teacher whose death in police custody sparked large protests.

Kenya's Office of the Director of Public Prosecutions said in a statement that the six suspects would be arraigned on Tuesday.

One of the police officers was the commander at the station where Albert Ojwang, a 31-year-old teacher and social media figure, was held in Nairobi.

It was not immediately clear whether the defendants were represented by counsel.

More protests expected

Ojwang died earlier this month following his arrest as part of an investigation triggered by a complaint by the deputy national police chief, Eliud Lagat.

Lagat had filed a formal complaint about allegedly false and malicious information published about him on social media, according to the state-funded police watchdog.

Police initially attributed Ojwang's death to suicide but apologised after an autopsy found that his wounds were the result of assault.

Ojwang's death prompted hundreds to protest police brutality over the past two weeks. Additional demonstrations are expected on Wednesday, which will also mark the one-year anniversary of a mass protest that culminated in the storming of parliament and several deaths by police gunfire.

'Cover-up'

Kenyan activists, who have been protesting Ojwang's death, immediately accused prosecutors of engaging in a cover-up by only charging low-level officers.

Lagat, who has denied any wrongdoing, stepped down temporarily from his post last week pending completion of the investigation into Ojwang's death.

One of the other officers charged with murder, James Mukhwana, told investigators that his superiors told him there was "an order from above" to have Ojwang roughed up when he came into the station, according to a copy of his testimony seen by Reuters.

Reuters has not been able to reach Lagat directly for comment and the National Police Service declined to provide comment on his behalf.