Interior CS Fred Matiang'i has directed the Inspector General of Police to deploy officers from the Internal Affairs Unit to investigate Thursday's incident where teargas was lobbed at an Azimio rally in Kisii.
A police officer discharged a teargas canister at the event that was being presided over by Azimio presidential running mate Martha Karua and Mama Idah Odinga.
The National Police Service on Thursday said it arrested the officer believed to be behind the teargas explosion that prematurely ended the rally at Kisii Stadium.
The explosion threw the rally into disarray and abruptly ended the event.
Three senior detectives from the internal unit left Nairobi for Kisii Friday morning to commence investigations into the incident.
The officers will submit their findings and recommendations to the Inspector General Hillary Mutyambai and the Office of Director of Public prosecutions for appropriate action.
The Kisii incident comes at a time recommendations by the Unit to ODPP advising criminal charges against two officers from Rioma Police Station who were suspected of murdering two people at Rioma centre in Marani subounty in June, 2021 is yet to be acted on.
In the Rioma incident, one person, a boda boda rider died while in police custody after he was allegedly beaten by police officers enforcing curfew orders.
At the same time, a police officer who was deployed to quell resultant riots sparked by the killing of the boda boda operator shot and killed a primary school pupil.
Four other people were seriously injured after sustaining gun shot wounds.
The case is still pending determination at ODPP one year down the line.
