If we consider the theory of a carefully planned crime, then it turns out that:
- The killer(-s) first conducted reconnaissance at night
- They waited patiently in the parking lot of Goddard School
- They knew that Liz would be at the garage sale that day (the video shows the killer purposefully approaching Liz)
- They knew when Sergio would leave and immediately drove to Liz's house afterward
- They knew the police would track the license plate and the car through cameras, so they made sure the car wasn't found (and it was never found).
- They knew the gun could be tracked, so they used a revolver (a gun that doesn't leave shell casings).
- They used disguise (at least in the video, the killer's hair looks like a wig).
-The killers didn't take smartphones or other devices that could be used to track them to the scene.
I don't completely rule out other theories, but for now we need to follow this logic and if we rule out luck, then this murder was well-prepared and planned by someone who knows how crimes are investigated and has either experience investigating them or experience committing them.
That is, it was either a current police officer, a former one, perhaps a military officer, or a professional criminal, a professional killer.
But this version is very at odds with the victim's profile—a simple, cheerful, and kind person, not involved in serious affairs or serious crime.
And this is a very serious problem. How then should we look at this crime? Was it simply a fortunate coincidence for the killers? More likely no than yes. There are too many coincidences and too much luck involved. This means we don't know something about the victim, and at the same time, this leads to some kind of conspiracy theory, but the facts also can't be ignored.
And here I have no answer for how to proceed.
About the end of your post.
It intuitively feels to me that Liz's killer is a professional hitman and the car is either not his or he got rid of it.
What group does he belong to? A cop, a military or a gangster? Who knows, some type of a pro.
The fact that he is a pro doesn’t imply that Liz was, nor that she was running in such circles.
To me it just shows that she somehow crossed paths with either a pro or someone around her who was able to contract a pro for the job.
And “the right pro” at this! Remember the Markel murder? Charlie Adelson had bad ideas but was not running in the proper circles himself. So his plan, to hire an assassin "known to his assistant" was that of a layman. JMO - whoever ordered Liz’s killing direct connections with the “hitmen”. Alternatively, the person could have set Liz up by asking her to sell something that dragged the “pros” attention.
In fact, the way Liz behaves during this moment, is indicative of her "not being a pro in any way”. Remember how her mom described Liz as “aware”? She likely was, the way organized people are. However, on the video, she doesn’t seem to have the instincts of a criminal. Even if she didn't like the person in front of her, but she did not run into the garage or to Nest. She just politely greeted the person.
The instincts of the people who are “aware the criminal way” are very different. On the videos of Olivia Pratt-Korbel’s murder case I watched, both the hitman (Cashman) and another gangster "target" (Nee) have very fast reactions. They seem to take in a lot of "horizon" around them, and respond to any avenues of safety that might open. This is why the case eventually got so tragic: criminals have very different reaction time compared to innocent civilians.
IMO there are many signs that would put Liz into the group of “innocent civilians”. That she could inadvertently be set up is another issue.
It’s good to see some renewed discussion around this case. Keeping attention on it is important.
We all know the truck seen on surveillance video (black or very dark colored Nissan Frontier Pro-4X) has never been identified, and it still feels like one of the most critical pieces of the puzzle to me. For a vehicle that distinctive to seemingly disappear without a trace is hard to ignore.
Does anyone here have any ideas that could help move the search for that truck forward? New tools or approaches—maybe even AI?
I suspect that by now the car has become a red herring. JMO. Using AI to answer a list of questions, random shooting or not, was the killer male or female, etc., and then run all the answers through AI again to get idas might be interesting.
Her dad's dying wish is for this to be solved. But frustratingly the perp seems to have covered their tracks well.
It was really the best lead. 
