If someone broke into a dwelling, would the homeowner call for police to investigate? How would violent crimes against community members be resolved?
There was a good answer here. Organized law enforcement in the States doesn't necessarily have its "roots" in slave patrols, but slave patrols certainly influenced and integrated into some parts of policing in the south. Night-watches, constables, and even sheriffs were already established systems that had a more notable impact on the structure and organization of policing. Then came along Robert Peel's ideas of policing in the early/mid 19th century in London, which the States adopted in an effort to keep up with mass immigration and industrialization.