While it seems pretty obvious the Tuttles are some of the big names involved with the Carcosa cult, I'm honestly hoping the yellow king is someone we haven't met at all.
We don't "know" who the spaghetti man is, people are suggesting it could be the lawnmower man or Ledoux, not that the lawnmower man is Ledoux. He's pointing out that if the spaghetti man was Ledoux, the heights are significantly different.
Or the simple answer to the question is that even if they caught Ledoux and he did kill Lange, anyone from the Carcosa cult could be responsible for the 2012 murder.
Ok, I recant my previous statement, this was the one entertaining part of the episode. "Zombie" Rick was hilariously awful, the rest was just boring and stupid.
Keep calling the fucking cops. Also, use that money you've saved over the past two months rent and get yourself a shotgun. I mean shit, you're in Texas. Don't get murdered.