He knows the street people by name and history, what they do for a living and whether they need to be caught for it. The businesses like community policing. Chinatown depends on tourists and walk-ins from other neighborhoods. Thugs and aggressive panhandlers don't help business. Foot guys like Halstead keep the lowlifes under control.
Asian crime exists.
Halstead took me to a brothel right on the street, an unobtrusive second-floor establishment. They'll see us on the camera and lock the doors. At the top, through a locked glass door, Halstead pointed to the small rooms used by the girls, who were nowhere in evidence. They run into the back room. They have done things, and still do.