Report by telephone:

(866) DHS-2ICE to “report suspicious activity” (866) 347-2423
(800) BE-ALERT (former Customs And Border Protection) (800) 232-5378

Report online:

DHS contact form for “immigration” or “security threats”
FBI online TIPS form for criminal activity
Email ICE: Operation Predator


A guide on how to report illegal aliens and criminal resident aliens:

DHS Version! By Juan Mann