The Mentalist: Season 2, Episode 14

2 - 14: Blood In, Blood Out

Cho helps the police with a murder investigation into David Song; a member of Cho's former gang, the Avon Park Playboys, and a fellow gang member of Cho's from his early days, and also used to be his best friend. Patrick insists on helping Cho with his off-the-books investigation, and so tags along