Anna Bakalis of United Teachers of Los Angeles writes a clarification:

Got this from the LASPD site:  Los Angeles School Police Department (LASPD)is the largest independent school police department in the United States, with over 410 sworn police officers, 101 non-sworn school safety officers (SSO), and 34 civilian support staff dedicated to serving the Los Angeles Unified School District (LAUSD). It is the fifth largest police department in Los Angeles County, and the 14th largest in California

The NYPD officers in New York City public schools are part of the New York Police Department, not an independent school police department.