Animal Cops: Houston (2003)

S1E14 The Rogue

Two of Bert's bodyguards are on duty protecting an erratic actress when one is suddenly shot dead. Nick is summoned to the scene, where he foils another assassination attempt, only to discover that the attacker is Frank Brennan, a man he believed to be dead after killing him four years earlier. Flashbacks reveal how Nick first crossed paths with Bert, saving him from Brennan, a rogue NSA agent intent on murder. It turns out Brennan isn't targeting the actress but is seeking revenge on those who were involved in his supposed demise, who are now her protectors. Together, Amanda and Nick stop Brennan from harming Bert while keeping the truth about Immortals hidden from Myers. In a tense confrontation, Amanda faces off with Brennan, who shoots her, but Nick retaliates, and Amanda ultimately beheads him.