Listen, I'm firmly against the current US drone policy when it comes to American Citizens.
However this is a unique situation. I'm not saying we should go bomb suspected terrorists who are US citizens. But when the guy is running around playing Rambo and killing cops, he forfeits his right to due process. He's killing cops and their families, he's a terrorist right now. Vigilantes don't target the families of people who have wronged them. Terrorism isn't insulated to the Middle East. He may not be waging war on the Great Satan, but he is waging war on the LAPD.
I do fear that it could be used as a gateway, but as I said, I think the drone policy needs to be amended as a whole. Even if they don't bomb him, drone could be useful in just locating the guy.