For investigators to know so little about this case, it strikes me as odd that they know it to be a premeditated, targeted killing.
In fact, I'll go out on a limb here and state that I simply don't believe they are at a place in the investigation to know if it really was a targeted killing.
From the outset, this has appeared to me to be a functional killing, i.e wrong place at the wrong time. It simply doesn't make sense that a smart killer would plan to execute a police officer in at an off-ramp by way of tree limbs and a shot gun.
Are these investigators not aware of Occam's Razor? The official narrative of Officer Ellis' murder is steadily violating more and more of its principles.