One also needs to consider the relative dynamic range of the camera/video in terms of both sensors and playback.

If the hardware is not capable of capturing sufficient dynamic range to be able to see into the shadows while driving in daytime/nighttime in this location, one must ask why not? That seems obviously negligent.

If the car can see into the shadows (say either with lidar or sufficiently sensitive hardware) then a self driving car either just failed to identify and predict the object and subsequently killed a pedestrian, or it detected them and killed them anyway.

If it killed them anyway, it may be that it was physically impossible for them to avoid the detected object, or forensics (if properly performed) would show that the collision was avoidable.

All of these scenarios seem pretty inconsistent with the hypothesis of the police chief knowing what the duck he's taking about, and I question what the hell he's doing releasing such a statement before the evidence is in...