Highlights from the Thirteenth Episode of Season 4 of Blue Bloods

Danny and Baez must track down a Marine veteran who kidnapped his son and beat his wife, and who Danny thinks is suffering from PTSD. Meanwhile, Frank is caught off-guard during a press conference by a woman who is seeking justice for her murdered daughter. Pictured: Donnie Wahlberg as Det. Danny Reagan. Photo: John Paul Filo/CBS ©2013 CBS Broadcasting Inc. All Rights Reserved.

Danny and Baez must track down a Marine veteran who kidnapped his son and beat his wife, and who Danny thinks is suffering from PTSD. Meanwhile, Frank is caught off-guard during a press conference by a woman who is seeking justice for her murdered daughter. Pictured: Chad Michael Collins as John Russell. Photo: John Paul Filo/CBS ©2013 CBS Broadcasting Inc. All Rights Reserved.

Danny and Baez must track down a Marine veteran who kidnapped his son and beat his wife, and who Danny thinks is suffering from PTSD. Meanwhile, Frank is caught off-guard during a press conference by a woman who is seeking justice for her murdered daughter. Pictured: Marisa Ramirez as Det. Maria Baez, Donnie Wahlberg as Det. Danny Reagan. Photo: John Paul Filo/CBS ©2013 CBS Broadcasting Inc. All Rights Reserved.

Danny and Baez must track down a Marine veteran who kidnapped his son and beat his wife, and who Danny thinks is suffering from PTSD. Meanwhile, Frank is caught off-guard during a press conference by a woman who is seeking justice for her murdered daughter. Pictured: Donnie Wahlberg as Det. Danny Reagan. Photo: John Paul Filo/CBS ©2013 CBS Broadcasting Inc. All Rights Reserved.

Danny and Baez must track down a Marine veteran who kidnapped his son and beat his wife, and who Danny thinks is suffering from PTSD. Meanwhile, Frank is caught off-guard during a press conference by a woman who is seeking justice for her murdered daughter. Pictured: Donnie Wahlberg as Det. Danny Reagan. Photo: John Paul Filo/CBS ©2013 CBS Broadcasting Inc. All Rights Reserved.

Danny and Baez must track down a Marine veteran who kidnapped his son and beat his wife, and who Danny thinks is suffering from PTSD. Meanwhile, Frank is caught off-guard during a press conference by a woman who is seeking justice for her murdered daughter. Pictured: Donnie Wahlberg as Det. Danny Reagan. Photo: John Paul Filo/CBS ©2013 CBS Broadcasting Inc. All Rights Reserved.

Danny and Baez must track down a Marine veteran who kidnapped his son and beat his wife, and who Danny thinks is suffering from PTSD. Meanwhile, Frank is caught off-guard during a press conference by a woman who is seeking justice for her murdered daughter. Pictured: Chad Michael Collins as John Russell, Donnie Wahlberg as Det. Danny Reagan. Photo: John Paul Filo/CBS ©2013 CBS Broadcasting Inc. All Rights Reserved

Danny and Baez must track down a Marine veteran who kidnapped his son and beat his wife, and who Danny thinks is suffering from PTSD. Meanwhile, Frank is caught off-guard during a press conference by a woman who is seeking justice for her murdered daughter. Pictured: Marisa Ramirez as Det. Maria Baez, Chad Michael Collins as John Russell, Michael Capperella as Tommy Russell. Photo: John Paul Filo/CBS ©2013 CBS Broadcasting Inc. All Rights Reserved.

Danny and Baez must track down a Marine veteran who kidnapped his son and beat his wife, and who Danny thinks is suffering from PTSD. Meanwhile, Frank is caught off-guard during a press conference by a woman who is seeking justice for her murdered daughter. Pictured: Donnie Wahlberg as Det. Danny Reagan. Photo: John Paul Filo/CBS ©2013 CBS Broadcasting Inc. All Rights Reserved.

Danny and Baez must track down a Marine veteran who kidnapped his son and beat his wife, and who Danny thinks is suffering from PTSD. Meanwhile, Frank is caught off-guard during a press conference by a woman who is seeking justice for her murdered daughter. Pictured: Chad Michael Collins as John Russell, Donnie Wahlberg as Det. Danny Reagan. Photo: John Paul Filo/CBS ©2013 CBS Broadcasting Inc. All Rights Reserved.

Danny and Baez must track down a Marine veteran who kidnapped his son and beat his wife, and who Danny thinks is suffering from PTSD. Meanwhile, Frank is caught off-guard during a press conference by a woman who is seeking justice for her murdered daughter. Pictured: Donnie Wahlberg as Det. Danny Reagan. Photo: John Paul Filo/CBS ©2013 CBS Broadcasting Inc. All Rights Reserved.