Katoyi was shot dead when he and a colleague were ambushed after attending to an assault complaint in Site C in Khayelitsha early this month.
Police spokesperson Novela Potelwa said a team of detectives comprising the Hawks arrested the 32-year-old suspect on Friday. They were still in pursuit of more suspects.
Katoyi’s family commended the police and hoped that more suspects would be arrested in due course.
The family’s spokesperson, Monwabisi Jobela, said: “It is good news that someone was arrested.