First of all...he's making money illegally. Secondly, it's probably money laundering (which is big bidness).
Since he had a ton of money, suicide is a low probability.
Was he the shooter? Was he a patsy? Was he set up?
Who knows. But guys with a lot of money they "earned" don't commit suicide. They first use their money to seek an answer to their pain.
Drugs, women, alcohol.
Counterfeiter?