Preliminary investigations showed that his eyes had been gouged out, before his body was dumped in a metal box by a roadside, local media report.
Rights groups have linked Chiloba’s killing to his sexuality, but the motive is still unclear.
Police said on Friday they had detained his long-time friend over his death.
He was described by police as the main suspect.
Police said they had arrested three more suspects on Saturday, and they had also seized the vehicle thought to have been used to dump Chiloba’s body.
It was found on Tuesday in a decomposed state by the roadside near the the western town of Eldoret.
Tributes on social media described Chiloba, who was in his mid-20s, as “an amazing human” and an “iconic fashion designer”.
He had moved to Eldoret from the capital, Nairobi, in 2019 to study fashion and was beginning to make a name for himself in design, a friend said.
Last month Chiloba wrote on Instagram that he was “going to fight for all marginalised people”, saying that he himself had been marginalised.
Human rights groups have called on police to swiftly resolve his killing.
