I am glad the police are not taking it lightly.
Hmmm-------------only a "good chance" of being charged???
Being involved in an accident is not in itself criminal. You need to have done something illegal or criminally negligent for it be criminal and to get charged. This sounds criminally negligent, but it's hard to say without reviewing all the evidence and testimony.
There's not nearly enough information for anybody to draw conclusions.
Factors like sight lines & speed and the actual impact details play into these accidents (it's an accident until there's evidence showing negligence).
One of the most serious issues with sidewalk bicycling is that drivers crossing the sidewalk at driveways and corners, sight down the sidewalk looking for pedestrians, and therefore don't look that far down the sidewalk. A bicycle moves faster and can easily bridge the distance from beyond the area checked to the point of impact.
We all do this at intersections, sighting and timing based on the expected speed of approaching vehicles. I don't know about others, but I've often found myself surprised by a car moving much faster than I allowed for, ie. doing 50 in a 30 zone. Likewise a truck driver miss or mistime a bicyclist where he's looking for pedestrians.
Add a few parked cars curbside, and it's easy to see how this could be something other than negligence. Not saying it is, just saying that without any details, all kinds of possibilities exist.