[s10e17] Breath Play Here

The episode includes several notable quotes, as seen on the Criminal Minds Wiki and IMDb :

Victims are found in their beds with their wrists tied with scarves, sexually assaulted, and eventually strangled with nylon rope. [S10E17] Breath Play

The UnSub, later identified as Patrick Jon Murphy, targets women he meets through online book clubs. He recreates consensual BDSM scenes from the novel before his own violent fantasies take over, leading him to murder the victims via erotic asphyxiation. The episode includes several notable quotes, as seen