This is a pretty comprehensive article about the type of scamming the guy who got killed allegedly did, from 2018, but somehow he kept getting away with stuff and didn't get convicted yet. I guess he afforded good lawyers and nothing caught up to him yet until this one disgruntled guy.
When I first heard about the shooting I assumed it might've been a scammer who got killed, because those small-time mortgage brokers can get really sketchy really quickly.