Another party heard from that the gang reports were cover for what the Eagles had already decided to do.
http://www.phillymag.com/birds247/20...e-desean-move/
He points out the contact by police over the murder investigation was in 2011 and 2012. If it had been a deal breaker, they had a long time to act on it. The other article I linked to gives an anonymous quote that the new "management" of the Eagles didn't know, but Howie Roseman (as GM) and the owner were both with the team at that time. If the knowledge wasn't passed along, that would represent a pretty big failure.
However, Kelly could have decided after a year it wasn't all worth the trouble.