UnitedHealth CEO shot
It remains highly unlikely that there will be a trial - purely on the probability, it almost never happens.
But also, it's already clear that he's guilty well beyond a reasonable doubt. The prosecution can connect Mangione to the gun (the one he had at arrest was at the scene of the murder hundreds of miles away) and they can put Magione there based on fingerprint evidence. Beyond that, the video evidence clearly matches his build and facial structure - by itself it's less compelling but with the gun and fingerprint evidence, becomes the final glue that makes it ironclad. The only thing more prosecutors could have would be an admission.
There's first going to be the question of his mental competency - which is hard to judge at this point. He seems fairly coherent and calculating, though those aren't the standards. But I suspect he'll be judged competent.
Then it becomes a question of what plea is offered and just how much he really wants to go to trial where he may be able to find some sympathy for the jurors . . . although that's much, much harder than people realize. It's easy to call him a folk hero standing up for the grotesque injustice that is the healthcare insurance industry but it's a symbolic killing - there was no actual relationship between the Mangione and Thompson. After the end of a competent and very clear case of murder is presented, and the jurors instructed about their duty to the law from the judge in what is a very sober environment, the likelihood of a Robin Hood scenario here is very, very low.
Everyone around him is going to be strongly encouraging him to take the plea.