IPOA has launched investigations into the killings of 18 people by police officers within a week under unclear circumstances.
The agency said the probe will be with a view of unraveling the circumstances that led to the fatal shootings.
"More particularly, the focus will be on whether the police officers were justified in the use of their firearms," the authority said in a statement on Tuesday.
The probe follows an incident in which three suspected robbers were shot and killed in separate incidents in Huruma and Mathare on October 29.
A day before then, six suspected robbers were gunned down in Dandora while three others were killed in Kerugoya.
IPOA is also looking into a case of an AP officer of Kegonga police division, Migori, who allegedly shot a man dead in unclear circumstances.
The oversight body said it will also probe a case in Yatta where three suspects were shot on October 23.
The probe will also factor some two other suspects who were fatally shot in Burma, Nairobi county on October 22, IPOA said.
"All these killings were committed by police officers on duty," the agency holds.
IPOA has been criticised for no good record of convictions of officers linked to such cases. Only four cases have been concluded by the agency.
However, the authority said, if found culpable, the responsible officers will face the full force of the law.
It said this will be through the appropriate criminal and/or disciplinary recommendations to the Director of Public Prosecutions and other suitable government agencies.