The Season 10 episode "Fog of War" follows a similar "case of the week" formula as most other episodes in the series, with Danny and Baez (Marisa Ramirez) working with the cowboy hat-clad Texas Ranger Waylon Gates (fan favorite guest-star Lyle Lovett) after the Lone Star Killer comes to New York. However, the episode's focus largely revolves around Eddie and her partner, Officer Addison (Justin Cunningham), who find themselves in a shooting. During the firefight, Addison fires on who he believes is a perp, only to find out she was actually an undercover police officer.
The death sends ripples through the entire department. It is always devastating for these characters when a fellow officer perishes in the line of duty. But it is almost unbearable when a fellow officer is gunned down by one of their own. The pain is palpable in a scene where Eddie gets into an uncharacteristic fistfight in the halls of the precinct, only to have Frank himself step in to remind all present how they should be honoring their fallen comrade.
Frank later convinces Addison not to turn in his badge because of the shooting. Another result of the shooting was Internal Affairs investigating Jamie for his inability to supervise. There were wide-reaching impacts throughout the series cast, all because of the death of an officer due to a case of mistaken identity.
