A Kenyan police officer has appeared in court on Friday in connection with the death of a teacher and blogger in custody, a case that has ignited public outrage and renewed scrutiny of police brutality in the country.

Albert Ojwang, 31, died in police custody last weekend after he was arrested over social media posts criticising a senior officer.

Police initially said Ojwang had fatally injured himself by banging his head against a wall, but a government pathologist later found the wounds were "unlikely to be self-inflicted".

Constable James Mukhwana, who was attached to the Nairobi Central Police Station, was arraigned in court by officers from the Independent Policing Oversight Authority (IPOA).

The watchdog requested three weeks to complete its investigation, telling the court Mukhwana was present on the night Ojwang was booked by Directorate of Criminal Investigations (DCI) officers.

Police spokesman Michael Muchiri confirmed to AFP that a constable had been arrested over the incident, but referred further questions to IPOA, which did not respond to a request for comment.

Simmering anger

Earlier in the week, Muchiri said five officers had been removed from active duty, to "allow for transparent investigations".

President William Ruto has called for a swift investigation, and promised on Friday that the government would "protect citizens from rogue police officers".

IPOA recently reported 18 people have died in police custody in the past four months.

Ojwang's death has become a catalyst for simmering anger over a spate of abductions that followed mass anti-government protests last year, reviving long-standing allegations of police brutality in the east African nation.

Protesters have called for the resignation of Deputy Inspector-General Eliud Kipkoech Lagat, whom Ojwang had criticised online.

Rights groups say dozens of people were illegally detained in the aftermath of last year's rallies, with many still missing, and others have been arrested for criticism of Ruto and the government.