I don't think it's that outrageous that Devon would be one of the first to jump on the "Kevin did it" band wagon. I mean, Devon never liked or trusted Kevin ever since he heard what Kevin did to Lily. Remember, before he was adopted, he was crush'n on Lily and was very protective of her. And the fact that everyone knows/believes Kevin was capable of murder at one time - and it's the same victim, Colleen, so I don't see it as out of character for either him or JT for that matter to believe Kevin did murder Carmen and hence blame him lickity-split. JMO.