Kenya protests: People face police brutality after dozens killed

But the investigation into the killing of Mr Masai has not yet resulted in the start of a prosecution, as investigators seek to gather more evidence and record statements.

Mr Waiganjo did not comment on this specific case but explained that when investigating injury or death the IPOA needs information on where the guns involved were from and the identity of the officers allegedly involved.

The BBC has verified a video filmed around the same time and likely the same place that Mr Masai was killed, showing what appears to be a plain-clothes police officer shooting at a crowd of protesters who were fleeing along a street.

Mr Njuguna says he thought his friend was profiled by the officer who shot him because he had dreadlocks.

“He was accused of stealing a phone. There was a shop that was looted. So, they thought he was one of the looters, so they shot him – because of what? Dreadlocks,” he tells the BBC, sounding angry and frustrated.

On the night he was killed, Mr Masai’s family says the doctor who pronounced him dead confirmed there was a bullet lodged in his thigh, with a wound visible on one side but no exit wound on the other.

“When I got to [where he died], I asked the medics to uncover my son’s body,” his mother, Gillian Munyao, told the BBC a day after the incident. She saw where the bullet had entered his leg.

After the autopsy, the family and friends of Mr Masai were shocked to learn that bullet could not be found in his body. They suspected that it was removed at some point.

When the BBC told Mr Waiganjo of the allegation of a lack of physical evidence, he was not surprised, given the IPOA’s own challenges securing items to aid their investigations.

This can derail the quest for justice despite the IPOA’s powers to compel institutions to hand over any vital information.

The BBC contacted acting head of police Douglas Kiricho for a response to the allegations of obstructing investigations and of using excessive force against protesters.

While he acknowledged the request and instructed the police spokesperson to respond to our specific questions, no response had been received by the time of publishing this story despite multiple reminders.