S4·E17 Shibboleth

When Phoebe Morton is murdered on the phone with a 911 operator, Goren and Eames take the case and soon realize Morton is one of five women murdered with a similar bent, the killer known as Body By Jake (B.B.J.). Their investigation leads them to Keith Durbin, a recently released parolee who seems to be perfect. Goren has his suspicions about Durbin, who doesn't seem right to him, and when they learn that there are similar killings going much further back, Goren and Eames soon focus their attention on a new suspect, and soon realize that even though he's not guilty, Durbin is the key.