If you see someone spray painting... that is a crime in progress. Do your best to take down all identifying information and call 911 immediately and report it to local police. If you see graffiti in your neighborhood, call the Graffiti Hotline in your area. You can also call these numbers to get graffiti removed from your neighborhood:

Graffiti Hotlines:
Clark County: 455-4509
Las Vegas: 229-6615
North Las Vegas: 633-1871