So, what’s your definition of suspicious? Someone with long hair? Or, a guy with no hair? What about someone with a ton of tatts? Talk to the experts, and none of those items are on the list. A suspicious person is an individual thing, says Robert Gardner, the CEO of CrimeWise, but it’s based more on behavior than looks. Take, for example, someone wandering through a neighborhood who just does not look like he belongs Another example is the guy who walks up to several front doors, rings the doorbell and then disappears around back. When you’re hanging out around your home, those are the kind of things that should put you on notice.