We know that there was never any sign of foul play. In fact, there STILL is no sign of foul play - other than the family/friends saying it is out of character for Steven to walk away. People say that all the time and it's not always true. Then again, NEVER has there been any trail pointing revealed as to why he was in the Vegas/Henderson area which, in and of itself, is suspicious to ME.
Honestly, I think every possible theory has been floated here, yet Steven is still missing. What has yet to be investigated is out of our hands. LE needs to step up and look deeper into what is known. Whether they will or not remains to be seen.
I do believe the answers are already there, they just need to be flushed out. For all we know, they are being flushed out.
Frustrating.