Blue Bloods Season 1 Episode 17 (03/11/11)
Danny feels personally responsible for finding the killer of a former U.S. Marine this week.
-Troy Cassidy, Mark Fallon, and Ian Seroy harass, attack and kill a homeless Marine in an alley. Danny and Jackie investigate the case.
-Ian is spotted on surveillance video with blood on his coat and quickly gives up the other two men. A homeless woman was also a witness to the crime but Erin tells Danny that their testimony may not be enough to convict. They need physical evidence.
-Danny relates to the victim as a fellow Marine and is infuriated by Cassidy's smug attitude. Danny and Jackie find a witness that saw Cassidy throw a bag into a dumpster and they find his bloody coat and the Silver Star he stole from the victim.
-Danny goes to arrest Cassidy without backup and a fight ensues. Danny comes close to killing the man but stops himself just as Jackie arrives.
-A story in the paper makes it sound as though Frank has aspirations to run for mayor. He quickly finds out that the story was planted by the mayor himself to reduce Frank's popularity with the public. When Frank confronts him, the mayor reminds him that he should take one for the team as Frank only has his job because the mayor appointed him to it.