S/He or they are waiting for the weekend . It was all over the media Monday that shooter(s) went two weekends without shooting, so following the pattern means proving everyone wrong and doing it ON the weekend. I sure hope I'm wrong, but you have to look at it.
I hope you are totally wrong, but your theory is not dismissible.
FOX news just had someone on, another profiler, didn't have a pen handy so couldn't write it down). He thinks it's terrorists because if you look at each place they've shot, they're main arteries into DC, and they're intending to inflict economic damage into DC first, because of the killings.