Which law mandated the activation of the Internal Affairs Service in the PNP?

The law that mandated the activation of the Internal Affairs Service in the Philippine National Police (PNP) is Republic Act 8551. This legislation was enacted to establish an internal mechanism within the police force aimed at ensuring accountability and transparency. By creating the Internal Affairs Service, the PNP was given a dedicated entity responsible for investigating police misconduct, thereby enhancing the integrity of the organization and maintaining public trust.

This act recognized the importance of having an independent body within the police institution that could address disciplinary issues and ensure that officers adhered to the standards of professional conduct. The establishment of the Internal Affairs Service under R.A. 8551 represents a significant step towards reforming and modernizing the police service in the Philippines. In contrast, the other options pertain to different laws that do not specifically address the creation of the Internal Affairs Service.