Four people have been arrested over the killing of a police officer on Friday along Thika Road.
Martin Korir, a DCI officer based at Ruaraka police station, was shot dead in the incident on Friday night.
Korir had been on his way home when a gang attacked the Neo Kenya vehicle and searched the passengers.
He was robbed of his Jericho pistol, that had 10 bullets.
The four suspects include the crew of the bus.