--- The City of New York is a queer duck as compared to other Cities in the USA. New York City consists of five boroughs, each of which is a county of New York State. The five boroughs—the Bronx, Brooklyn, Manhattan, Queens, and Staten Island—were consolidated into a single city in 1898. Thus you have a City that is made up of 5 Counties. It also happens to be the most densely populated major city in the United States.
--- Whereas most counties have an elected sheriff the City of New York is different. As NY City is a class One City it has different rules and powers than other cities and since it covers all 5 counties it has elected to have a City Sheriff rather than to duplicate services and have a different Sheriff's agency in each Borough.
--- (1) [[[ The New York City Sheriff's Office, officially the Office of the Sheriff of the City of New York, is the primary civil law enforcement agency of New York City and the enforcement division of the New York City Department of Finance. The Sheriff's Office is headed by a sheriff, who is appointed to the position by the mayor, unlike most sheriffs in the U.S. state of New York who are elected officials. The New York City Sheriff holds jurisdiction over all five counties within the city, with a subordinate undersheriff in charge of each county-borough. Deputy sheriffs of various ranks carry out the duties of the sheriff's office.
--- The New York City Sheriff is the chief civil law enforcement officer for the City of New York. Responsibilities of deputy sheriffs include revenue collections in civil litigation situations; collecting funds or making arrests for parents in arrears of child-support payments; and collecting on moving violations, parking violations, and judicial judgements. They handle the enforcement of judgments for both small claims and supreme court. Such responsibilities may involve collection of unpaid taxes, enforcement of unpaid environmental fines, seizure of property and evictions. The sheriff may sell real estate and personal property to satisfy judgments, or perform arrests ordered by the civil court system. The sheriff's office has also become involved with cigarette-tax enforcement as well as assisting the NYC Department of Buildings in enforcing stop work orders. In addition, the sheriff sells vehicles not recovered by their owners, checks towed vehicles to determine if they are stolen, and enforces court judgments through a variety of programs.]]] (1)
--- So the Office of the City Sheriff handles Civil Law and Civil Process and the NY Police Department handles criminal inquiries, criminal reports, criminal investigations, criminal forensic investigations, arrests of criminal suspects, the suppression of criminal activity, traffic enforcement and general police services through out the 5 Boroughs or City.