[Alice in Wonderland]

Was Martin strolling along toward home with purpose and a destination, or was he moving slowly and aimlessly? Was he stopping to peek into parked cars? Did Martin take a "shortcut" across private lawns? Did he look like he was "casing" a house?

From what I've read on this thread, Martin was talking on his cell phone with his girl friend while returning from the store with a soda and a bag of candy.

[Jonty30]

Considering Mr. Zimmerman’s tendency to be hyper-vigilant, I can see him interpreting Martin’s cellphone activity as one of calling his homeboys, after casing some joints.