One thing I noticed about the video is it seems to be all about other people's property than the owners property. The way the camera is angled it would not seem to offer much help in security aspects of the owners property. Perhaps it is by design of the total security cameras system this one camera offers a long range shot of street and adjoining property. Question I have though is how do we know this is the stepmom and boy? All I can get from the video is there are 2 people who entered the truck. This doesn't provide positive ID in my opinion. MOO.
That's probably where the audio comes in.