Detectives tracked forensic leads to Kampala's Kyanja Heights flats, arresting Police Constable Bett Kiplangat Collins and civilian Pius Muiru Mbugua with Uganda Police help; a third, Samuel Karanja Gathoni, was stopped in Nairobi.
PC Bett allegedly surveilled and co-drove the Land Cruiser that boxed in Dr. Mutiso's car, while Muiru handled payments for the hit team. The DCI dismissed rumors of suspects escaping to Uganda, crediting public tips and cross-border cooperation, as the probe seeks the full network behind the slaying.