The mob knows how to make good waterproof cement that doesn't float....about 50 miles offshore would do it...
I do recall a case on TV where some fishing boat or diver found a body that was just a skeleton wrapped in chains or such..the guy had a Rolex and the FBI traced its serial number back to the owner and eventually made a conviction! Persistence, something that would probably be lacking should something bad happen to the 3 amigos...somehow I don't think there story would be on the news everynight trying to find out what happened to them..maybe a week then on to a new political scandal...
That is AMAZING! When an investigation is done right, it can be breathtaking, can't it?