Attempt on Leo's life.

That doesn't really make sense does it? If he had killed Leo at the hotel no one would be able to question him about the money. Unless, maybe he was going to kidnap Leo and was just using the gun as a weapon--it only became a bigger deal because Riggs and Murtaugh were there.
Also, Leo says they are after him because he laundered the money, but aren't they after him for stealing some of the laundered money? Unless the half-billion in laundered money was the money he stole?