[Last Dakotan]

The trio hadn't demanded money and left as soon as the shot was fired.

My guess is they already had their bag limit of clerks filled.

[Cindy]

OPINION -SPECULATION: It could be the suspects were inexperienced and scared.

Or maybe...

It could be something like a crime spreee Oakand, California experienced.

http://www.freerepublic.com/focus/keyword?k=oakland

However, it’s too early to tell — not enough details.