Blue Bloods season 4

The fourth season of Blue Bloods, a police procedural drama series created by Robin Green and Mitchell Burgess, premiered on CBS September 27, 2013.

[2] Donnie Wahlberg, Bridget Moynahan, Will Estes and Len Cariou are first credited, with Tom Selleck receiving an "and" billing at the close of the main title sequence.

[4] Also appearing regularly and receiving "special guest star" billing are Gregory Jbara as Deputy Commissioner of Public Information Garrett Moore, and John Ventimiglia as Chief of Department Dino Arbogast.

Both Frank and Erin are reluctant to reopen the case, fearing it will jeopardize the other three convictions, until a witness in the Lowe murder indicates that the detective in charge coerced him to pick a certain photo out of a lineup.

Danny suspects the soldier has PTSD, and the case brings back painful memories of his own time as a Marine in Iraq.