Enforcement or utilization of criminal law in defense of arrested persons

What kinds of state and local agencies that concentrate on criminal law enforcement or defense of arrested persons are in operation around the country? The United States is divided into five regions: Northeast, Southeast, Midwest, Southwest, and West. Do a search and select an agency from each region. Specify the name of each agency, state wherein located and region. Explain how that agency enforces criminal law or utilizes criminal law in defense of arrested persons.
For example, the Oakland Police Department is in California, representative of the West region. Since it is a municipal law enforcement agency, it enforces criminal law. The Alameda County Public Defenders Office is in California, representative of the West region. It defends persons who have been arrested in either the county municipal court or superior court. You could choose either of these agencies.
Another example. The Vermont State Police is representative of the Northeast region. Since it is a state law enforcement agency it enforces criminal law. The office of the Windsor County States Attorney is in Vermont that is representative of the Northeast region. It prosecutes persons who have been arrested in the district court or county court. You could choose either of these agencies.
Explain the duties for each agency whether it be criminal law enforcement, prosecution, or defense of arrested persons. Ascertain some information about each agency. Include methods employed in pursuit of accomplishing their mission?
Scoring for this assignment will be based on how well you comprehensively explain what information you learned from your research, all clearly written and formatted in just 4 pages of main narrative.