The school shooting could be a copycat with a similar calibre weapon or maybe even a false flag operation.
From what we have heard, it is likely the first wave of shootings were from a vehicle of some sort and with practically zero clues. This last shooting came after the weekend, changes the (very successful) shooting method and also provides a couple of very distinctive clues. It also apparently completely changes the scope and direction of the investigation - at least here on FR. Then the shootings have stopped, at least for a couple of days.
Except that they claim that they have a bullet match between the Monday shooting and several of the others.