The POS Devlin did tell Shawn he would be killed according to the stepdad. The part about Shawn thinking his family didn't want him is speculation according to this article.
Devlin must have been very confident that nobody would recognize Shawn. Or, if they did, would do nothing about it. Sadly, and amazingly, he was right.
Also Police Confirmed in an article in the st . louis newspaper that Child Porn was found on that piece of crap Devlin's computer