I know this is an old original post, so I'm almost certainly too late. I don't see the crime being committed, but if we assume it was murder or something important enough that police would follow through, I think the perp could be found.
We have a couple facts:
The colors don't match your state.
The size of the letters don't seem to match ANY state, and very few states use black and yellow.
Therefore, I think it's a dealer plate, which means the vehicle was probably purchased new within the preceding 30 days within a 50-mile radius.
Find the nearest dealer with a yellow-on-black logo. If it's important enough, police could query that dealer for all trucks of that model, in that color, sold within 30 days. Depending on the size of the dealership, that may narrow it down to one.
I speak as an authority... I'm a super-secret quadruple agent working for four countries, unknown to my employers: Nigeria, North Korea, Santa's Workshop (Recognized by the UN as a sovereign nation in 1972) and the well-known country of BFE. Please don't tell. Especially Santa.