Private security forces and official law enforcement officers have similar clients and stakeholders. However, their clients and stakeholders are not exactly identical.
The client of the private security force is the entity that has hired it. These security forces are created and maintained for the benefit of the entity that hires them, not for the benefit of society at large. So, if a shopping mall has its own security force, the mall is the client of that force. By contrast, public law enforcement agencies have a much less identifiable client. Essentially, the entire community is their client because these agencies are created and maintained in order to keep the peace in the community as a whole.
The stakeholders of these two types of organizations are similar. In both cases, everyone who comes into contact with them is a stakeholder of some sort. In the case of a mall security force, each person who enters the mall is a stakeholder because the performance of the security force can have an impact on them. The businesses that operate in the mall are also stakeholders. In the case of the public law enforcement agency, the group of stakeholders is much more extensive. Since these agencies are responsible for the entire community, everyone is a stakeholder. The performance of the police (as well as things like the cost of having a police force) matters to every person in a community.
Ultimately, the individual officer (whether private or public) is responsible for their own actions. The security firm and the locality that operates the police force are somewhat responsible. They are responsible for training officers and for establishing rules that govern the officers’ conduct. If officers are well-trained and act within the rules, the security force or locality is responsible for their behavior. If, however, officers are poorly trained and/or if they disregard the rules imposed on them, they are personally responsible.