I don't know what is so complex about it, it's cut and dried physical evidence, it's not DNA, prints etc. It should be fairly straightforward.
The very first reports I saw were that the shooter used a Glock & a Sig Sauer inside the school. The same reports said a "Bushmaster assault weapon" was found in the car. Some said the trunk of the car.
Once the media picked up the term "assault weapon" from the initial coverage then it became a story about "assault weapons" and killing children.
I don't know what is so complex about it, it's cut and dried physical evidence, it's not DNA, prints etc. It should be fairly straightforward.
Physical evidence is never straightforward. Lots of stuff to get wrong.
It never is what it initially appears to be. Never.
Not the cops fault, but it is often like a Rorschach test. People, even good coppers, see what they WANT to see (well, sometimes criminal defense attorney see what they WANT to see too).
Wait and see what develops.