Season 10 of CBS’s Blue Bloods delivered the kind of gripping police procedural drama fans had come to expect. Frank Reagan (Tom Selleck), the steadfast patriarch of New York City’s most prominent law-enforcement family, faced fresh challenges with the arrival of a new mayor, Peter Chase (Dylan Walsh), whose leadership style often clashed with those around him. Erin Reagan (Bridget Moynahan) struggled to balance her demanding career with the emotional strain of her daughter moving across the country, while Jamie (Will Estes) and Eddie (Vanessa Ray) navigated both personal and professional tensions in their evolving relationship.
As always, death played a significant role throughout the season. With Danny Reagan (Donnie Wahlberg) investigating homicide after homicide, the toll of violence weighed heavily on him. Meanwhile, the loss of fellow officers struck Frank especially hard, stirring deep feelings of responsibility and grief. Each death left its mark but one tragedy stood apart from the rest.
An officer 
on officer shooting that shook the department
The episode “Fog of War” largely follows the show’s familiar case-of-the-week structure, with Danny and Baez (Marisa Ramirez) teaming up with Texas Ranger Waylon Gates (guest star Lyle Lovett) as the Lone Star Killer makes his way to New York. Yet the emotional core of the episode centers on Eddie and her partner, Officer Addison (Justin Cunningham), whose lives are forever altered during a chaotic shooting.
In the confusion of the firefight, Addison fatally shoots someone he believes to be a suspect only to discover she was actually an undercover police officer. The realization sends shockwaves through the entire department. Losing an officer is always devastating, but the knowledge that one of their own pulled the trigger makes the tragedy almost unbearable.
The emotional fallout is immediate and raw. Eddie, overwhelmed by grief and anger, becomes involved in an uncharacteristic fistfight at the precinct, prompting Frank to step in and remind everyone of the importance of honoring their fallen colleague with dignity. The tragedy also sets off a chain reaction: Frank later urges Addison not to surrender his badge, while Internal Affairs launches an investigation into Jamie for failing to properly supervise.
The repercussions ripple across the entire Reagan family and the department at large, all stemming from a single, devastating mistake. Among all the losses in Season 10, this death stands as the most heartbreaking one that underscored the heavy cost of duty and the fragile line officers walk every day.