We have no idea who is doing this.
We have no idea why he is (or they are)1 doing this.
There seem to be no common characteristic to the victims, except that they are Americans.
This could be terrorism. It could be a serial killer. We have no idea.
I don't recall President Bush commenting on the DC snipers, and I would not have expected it. I don't remember President Obama talking about any other serial killers, nor President Clinton, at least not until after they were apprehended.
This is nuts. The president has nothing he can do here that is not already being done by the local authorities and the federal agents.
1: I say "He", because while it is possible a woman is responsible, the chances are monumentally small.