S4·E16 Murder Through the Looking Glass

Jessica gets herself into a mess of trouble after overhearing the dying words of a professional hitman. When she investigates the murder of Adam Cosgrove, she soon discovers that no one seems to want to admit he's missing, let alone dead. With the help of a prickly police sergeant and a priest who isn't quite what he seems, Jessica discovers that the man who was killed was in charge of leading a top-secret government mission to protect a foreign diplomat, and that someone in the safehouse has gone to the other side.