Line of Duty Season 4

DCI Roseanne "Roz" Huntley identifies and captures a suspected serial killer. The suspect is uncooperative under questioning and appears not to have an alibi. After months of fruitless investigation, ACC Derek Hilton puts pressure on DCI Huntley to charge the suspect. FC Tim Ifield informs DCI Huntley of concerns he has relating to the forensic evidence, which he believes proves the suspect's innocence, but DCI Huntley seems uninterested. Ifield alerts AC-12 to a possible miscarriage of justice. He tells DS Steve Arnott that he believes DCI Huntley is deliberately ignoring forensic evidence which proves the suspect's innocence. Ifield explains the forensics suggest someone has manipulated the crime scene in an attempt to frame the suspect. With the authorisation of Superintendent Ted Hastings, DS Kate Fleming goes undercover to investigate DCI Huntley, and also interviews the suspect. Arnott informs DCI Huntley that AC-12 are investigating. DCI Huntley suspects Ifield and turns up at his house at night, where she accuses Ifield of talking to AC-12. Ifield admits this, and a row breaks out over the guilt of the suspect. DCI Huntley causes Ifield to burn his hand and he slaps her. When she accuses him of assault, he pushes DCI Huntley who hits her head, appearing fatal. Fearing the worst, Ifield departs to a hardware store, purchasing cutting tools in order to dispose of the body. Whilst preparing to carve DCI Huntley's head, she wakes up.