Why is everyone so convinced of his guilt?

This is a legit question, by the way. I'm not trying to argue anyone is wrong.

I didn't watch the entire trial, I just watched the documentary series and some snippets from the trial here and there (and a little extra just now, trying to answer the question I'm presenting here), but what was the concrete evidence that this guy killed his son and wife? And the good motivation for it, as well? I mean, I get that he ripped a lot of people off and wasn't particularly likable, but I can't recall seeing anything that made me think, "Yeah, he definitely did this," beyond a reasonable doubt.

In fact, from what I understand wasn't his son already hated and threatened by a significant number of people due to that boat incident (not to mention he was notorious for being an A-hole in general)? It seems perfectly possible to me that he could have perhaps just rubbed someone the wrong way and got blasted by one of the family guns that they apparently kept laying all over the place.

Again, I didn't watch enough of the trial to consider myself particularly well-educated about the situation, and I'm not saying I believe Alex Murdaugh didn't do it. But other than him matching the profile of the type of person we love to hate (rich, white, powerful, greedy, with political-level pull in his community), and his financial crimes, I just don't understand why everyone is so convinced of his guilt in this matter?