I think it is so that they can get a better view of the whole area instead of just lighting up one particular spot. It would make sense that they want to see as much as possible in case the suspect is still at the scene.
That makes sense, but I've always wondered why they don't just turn on a light. Or is it easier to catch things when you're just moving a flashlight over a dark area? I keep having internal debates with myself and can never come to a good conclusion.
It just occurred to me that this really isn't a lone thread topic... Please continue any discussion in the "questions about episodes, yada yada" thread. Thanks!