A police station in Western Kenya was set ablaze on Thursday after thousands of protesters marched with the coffin of a teacher who died in custody last month, local media reported.

Albert Ojwang, 31, was found dead in a police cell in the capital Nairobi after his arrest in Homa Bay County, his death sparking rallies against police brutality.

In videos shared online, which AFP could not independently verify, a large crowd of protesters is seen carrying Ojwang's coffin after it arrived in Homa Bay for a burial scheduled for Friday.

Media reported that during the procession protesters stormed and torched Mawego police station, where Ojwang was briefly detained before being transferred to Nairobi.

Killed in custody

Police initially claimed he had taken his own life until government pathologists found he had been killed.

Ojwang was arrested for allegedly criticising deputy police chief Eliud Lagat in online posts.

Lagat "stepped aside" during the investigation into Ojwang's death, but protesters called for his full resignation and charges against him.

Six people, including three police officers, have been charged over his murder.

Earlier this month, the Independent Policing Oversight Authority said 18 people had died in police custody in the past four months.