I'm not in any way suspicious, just because I have been around the area where a crime has happened. As we know those blocks can be quite large so you will have lots of "suspects" whose only connection to the crime is being around a crime scene.

Then you question all of them and hope that something sticks with one of them. That is unprofessional and will lead to lots of problems once your neighbours get to know that you are suspicious of $crime because you were near $location.