Kenyan authorities arrested a senior policeman on Friday in connection with the death of a blogger in police custody last week, the police watchdog said, in a case that has sparked violent protests and shone a spotlight on police misconduct.

The police apologised after initially claiming Albert Ojwang died by suicide in a cell in Nairobi's Central Police Station on Sunday, two days after his arrest. An independent autopsy pointed to assault as a more likely cause of death.

The policeman in charge of Central Police Station was arrested on Friday, along with a closed-circuit television (CCTV) technician called to dismantle the CCTV at the station, said Samati Kemboi, commissioner of the Independent Policing Oversight Authority (IPOA), the police watchdog.

The CCTV system at the station had been interfered with, and records "changed and formatted" in the early hours of Sunday, according to a report by IPOA, which is conducting an investigation.

The 31-year-old's case has drawn close scrutiny of the country's security services, which have been accused of extrajudicial killings and enforced disappearances for many years, a source of mounting outrage for many Kenyans.

Hundreds of protesters angered by his death demonstrated in Nairobi on Thursday. Vehicles were set ablaze, and police fired tear gas to disperse crowds, who called for the country's Deputy Police Chief Eliud Lagat to resign.

On June 4, Lagat filed an official complaint that an X account reportedly associated with Ojwang had published "continuous false and malicious publications" about him, the IPOA report said.