The details of the roles and functions of this national security organ are contained in the National Police Service Act, 2011 as enacted by Parliament in fulfillment of the Constitution:
239. (6) Parliament shall enact legislation to provide for the functions, organisation and administration of the national security organs.
As an organ of the state, the Police Service's primary duty will be to provide security to the individual and to the community.
238. (1) National security is the protection against internal and external threats to Kenya’s territorial integrity and sovereignty, its people, their rights, freedoms, property, peace, stability and prosperity, and other national interests.
As noted earlier, the Police have for a long time been viewed with mistrust and suspicion. It therefore comes as no surprise that the new expectation on the Police Service is that it is seen to be working to protect the Bill of Rights of the people of Kenya; its reforms must be geared towards this end. Excerpts from Article 244:
244. The National Police Service shall— (a) strive for the highest standards of professionalism and discipline among its members; (b) prevent corruption and promote and practice transparency and accountability; (c) comply with constitutional standards of human rights and fundamental freedoms; (d) train staff to the highest possible standards of competence and integrity and to respect human rights and fundamental freedoms and dignity; and (e) foster and promote relationships with the broader society.
The police will no longer conduct prosecutions - that responsibility now falls under the Director of Public Prosecutions, DPP; their role in criminal justice has been limited to that of investigations. Chapter 9 - The Executive, Part 4 - Other Offices, Article 157:
157. (4) The Director of Public Prosecutions shall have power to direct the Inspector-General of the National Police Service to investigate any information or allegation of criminal conduct and the Inspector-General shall comply with any such direction.
Article 157 also ensures that Police are accountable to the public (via the office of the DPP). In that regard, they must demonstrate a proactive and impartial mien at all times and especially when they may be inclined to act reluctantly in the conduct of an investigation or appear to cover up criminal conduct.