wajuaji, why does US has so many police units/departments CIA, HOMELAND SECURITY, FBI, SHERRIF OFFICE, NYPD*, MARSHALS, DEA etc. sijawaielewa kabisa…
Uliza guka.
jurisdiction
One branch watches the other and so on and so forth. Kama sasa Kenya KRA should have its branch of law enforcers. There should be another one for drugs and another one for cattle rustling (the two are small so they can be combined just like Trumpistan have ATF). There can be a branch that deals with PSVs alone. It’s very difficult to get away with a major crime in USA
CIA - Intelligence agent that works abroad.
HOMELAND SECURITY - created after 9/11. Equivalent of Interior Ministry.
FBI - Federal government law enforcement within the US border etc.
SHERRIF OFFICE - operate in the enforcement of civil suits/litigation. Example: kama haujalipa child support or rent 
and you are being sued or being evicted etc, hawa ndio wanakuletea summons to appear.
NYPD - each state, city, county has its local law enforcement.
MARSHALS - kukamata fugitives or wanted criminals.
DEA - Drug enforcement agency. Self expanatory.
ATF - Alcohol, tobacco & firearms - self explanatory etc.
They do work together towards law enforcement.
Kenia has a massive deficiency of this.
CIA-NIS
HOMELAND SECURITY-ATPU
FBI-DCI
SHERRIF OFFICE-AP
NYPD-Kanjo askari
MARSHALS-border patrol unit
DEA-Anti-narcotic unit
Federal jurisdiction: (Focus is mainly on criminal activities)
Secret service- protect the president, investigate (mainly) financial crimes i.e counterfeit currency etc.
FBI- Mainly investigative but has a police force
Border Patrol agents- Under Homeland Security
Park Police
ATF
DEA
State Level:
State Police- criminal, civil and traffic
Natural Resources Police
County Level:
Sheriffs and Deputies- criminal, civil and traffic
City Level:
City Police (not all cities have independent units; some rely of Sheriff’s office)- criminal, civil and traffic
Other Levels:
Campus Police (within college campuses and universities)