This discussion may contain spoilers!
so in the second episode we got a hint of some backstory with Carlos. when Sarah ask her father not to do something to Carver, and Luke quickly reply "of course he won't, Sarah, all right? your dad is the nicest man I know, which is why he's not going to do anything crazy or.....not nice. Right?" (Luke was trying to get Sarah not to worry, but some of that line was directed at Carlos) Carlos reply's to Sarah "you know these are bad people, sweetie."
then later in the episode, at least for the people who didn't went to find Luke and Kenny. When Carver was attacking Carlos he mention that Carlos killed a friend of his, George.
(EDIT: sorry Alvin killed George)
what do you guys think? did Alvin kill George trying to escape from Caver's comunity