My friend said to me, "the police caught a thief yesterday"
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Law enforcement in the United States has changed drastically since its founding. During colonial times and the initial forming of the country, law enforcement’s role in local communities was carried out by volunteer groups and part-time officers who were privately funded by local community members.
The first centralized, municipal police department was created by the city of Boston in 1838. This was quickly followed by the creation of similar agencies in New York City, Chicago, New Orleans, and Philadelphia. By the late 1800s, almost every major city in the country had created some manner of formal police force.
Today, there are more than 18,000 local, state, and federal law enforcement agencies who employ more than 420,000 officers. There is an average of 2.2 law enforcement officers for every 1,000 individuals living in the United States, and the size of police departments varies largely by location and population. For example, New York City, New York has 36,228 law enforcement officers while towns like Amherst, Virginia or Hot Springs, North Carolina have less than five officers each.
The rise of formal law enforcement agencies has also created a demand for formal police training and increased professionalism among members of the law enforcement community. Each year over 660 law enforcement academies provide basic, entry-level training for future law enforcement officers. Many institutions of higher education also provide programs for law enforcement careers. Between 2006 and 2013, the amount of time individuals spent participating in basic law enforcement training programs increased by two weeks and more than a third of these programs now require some form of mandatory field training.