But until the tokens are actually put in circulation there can't be any fraud. Also, from that website, they can't hide what they do in the end. Either they sell them, which we can see, or they just sit there, which we can see.
My guess is they were not "left behind" they were from a seed round or they are reserved for a seed round (the 12.4million), the rest will be Pre-ICO and ICO rounds. All are still accounted for.