Ep 4. Killer App

In season 13, episode 4 of Criminal Minds, titled "Killer App," the Behavioral Analysis Unit (BAU) is tasked with tracking down a killer who is using a social media app to target his victims.

The episode begins with the murder of a young woman named Jenny, whose body is found in an alleyway. The team arrives on scene and begins to piece together the evidence, including surveillance footage of Jenny leaving a bar with an unknown man.

As the BAU investigates, they discover that Jenny was using a social media app called "Polly," which allows users to anonymously post confessions and secrets. The team realizes that the killer is using the app to find and stalk his victims, and begins to narrow down their suspect pool.

Meanwhile, Garcia discovers that her own personal information has been leaked on the app, leading her to feel vulnerable and exposed. This subplot adds a personal and emotional element to the episode, as Garcia struggles to come to terms with the violation of her privacy.

As the team continues to investigate, they discover that the killer is targeting women who have posted confessions about cheating or infidelity on the app. They also link the murders to a man named Ryan, who works for the company that owns Polly.

The team races against time to track down Ryan and stop him from killing again. They use their profiling skills to determine Ryan's location and set a trap to capture him. In a tense confrontation, they are able to apprehend Ryan and save his intended victim.

The episode ends with Garcia taking a stand against the app and publicly denouncing its use. This storyline highlights the impact of social media and the dangers of oversharing personal information online.

Overall, "Killer App" is a thrilling and thought-provoking episode that explores the ways in which technology can be used for both good and evil. The episode also features strong performances from the cast and delivers an emotional punch with Garcia's personal subplot.