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Luigi Mangione, CEO shooting suspect, is a tech worker
(www.bbc.com)
This is a most excellent place for technology news and articles.
He was CEO, not founder. The dude was only worth around $50 million. The shooters family owns a country club and an entire chain of nursing homes. They almost certainly have more money, probably a lot more money.
I can't answer your other questions. Perhaps the answers will be in his manifesto.