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Security Guards from WikiPedia:

A security guard, (or security officer) is usually a privately and formally employed person who is paid to protect property, assets, or people.

Often, security officers are uniformed and act to protect property by maintaining a high visibility presence to deter illegal and inappropriate actions, observing (either directly, through patrols, or by watching alarm systems or video cameras) for signs of crime, fire or disorder; then taking action and reporting any incidents to their client and emergency services as appropriate.

Since at least the Middle Ages in Europe, the term watchman was more commonly applied to this function. This term was carried over to North America where it was interchangeable with night-watchman until both terms were replaced with the modern security-based titles.

Many security firms and proprietary security departments practice the "detect, deter, observe and report" methodology. Security officers are not required to make arrests, but have the authority to make a citizen's arrest, or otherwise act as an agent of law enforcement at the request of a police officer, sheriff, and others.

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