The Mentalist Season 4 Episode 8 (11/17/11)
-Yolanda Concepcion, a cop is shot and killed while working an undercover narcotics assignment at a night club.
-Yolanda's was investigating drug lord Omar Vega who ran the club but they couldn't find his drug headquarters.
-Jane goes undercover to find Vega's drug headquarters but Cho and Rigsby lose his tracking signal.
-Cho questions a hooker named Summer who gives him information on the whereabouts of drug lord Omar Vega.
-While facing Vega, Jane finds out that Yolanda's partner, a dirty cop killed her when she got too close to the truth.
-With Summer's information, the CBI team find and rescue Jane.
-Cho asks Summer to be his confidential informant.