I could accept this if the motivation for the crime began with robbery. At this point, I don't think robbery was the motive. I'm always open to changing my mind, though.
Plans in the developmental stage for work? She was very intelligent. Or perhaps they wanted nothing at all--just got their jollys rumaging through her things after they finished with her.
Personally, I think it speaks more to the blurriness and distortion from the very old camera, than to the truth of the matter.
If robbery was not a factor, then why take anything other than the phones? Curiosity? Attempt to make it look like a robbery? Of course, getting off on going through her stuff after they were done - that is one cool and confident person (or very dumb) to believe they are someplace where they won't be seen and take that additional time. As far as the video I believe it should be processed again - has science advanced enough to do something else?