Their Solitary Way

The police interview begun at the end of the previous episode continues. Spector, with Sean Healy and Louise Wallace beside him, gives his account of how Susan Harper died in London in 2002. He and David Alvarez met her at a club and she invited them back; she and Alvarez had sex while Spector watched; and when Alvarez went out for more drink, Spector suggested something else. He puts the death down to a sex game that went too far, describes the method as autoerotic asphyxiation with a plastic bag, says he cleaned the scene and left, and cannot explain why Alvarez took the blame. He then moved back to Belfast and changed his name from Peter Baldwin to Paul Spector.

DSU Stella Gibson lets him talk, then challenges the performance. When he taunts her with "She speaks", she answers with Alvarez, "He said he felt in your debt", and takes the account apart: she tells Spector that Father Jensen abused him as his chosen boy, that he suffered the worst of it, and that when he had to name a successor he passed over the boy he could have named. She tells him his need for a captive audience is infantile and the whole thing a performance. Spector, angry, admits that when he first heard what he had done he was horrified, but that it began to intrigue him. Healy asks for a break; as Gibson and DS Tom Anderson move towards the door, Spector punches Gibson to the floor and stamps on her, and when Anderson pulls him off, Spector breaks Anderson's arm. Several officers restrain him. Both are taken to hospital; Gibson's injuries are less grave than they look. Word reaches ACC Jim Burns, drinking again; he tries to get at Spector and has to be held back.

At the secure unit, Dr Larson tells Spector he can be treated but cannot be cured, which closes any insanity plea resting on the claimed amnesia. Later, Gibson visits Katie Benedetto at the juvenile detention centre, where Katie has been self-harming with a bone taken from a meal. Gibson does not lecture her; she tells her that Spector does not care about her and that she will throw her life away if she keeps trying to earn his attention. The two of them talk about their dead fathers.

Spector then acts. Before the killing he recites a poem about death to Bailey, "And when my heart began to bleed; 'Twas death, and death, and death indeed". He persuades Bailey to create a disturbance in the unit's lounge; in the confusion Spector gets free, knocks Dr Larson unconscious and takes his belt. He reaches Bailey's room ahead of the staff, who bring Bailey back there struggling, and strangles him with the belt. He then puts a plastic bag over his own head, loops the belt around his neck, fixes it to the back of the door and hangs himself, the method his mother used on her bedroom door when he was eight. When the staff reach him, he is dead. Gibson comes to the unit, looks at the body and leaves. Burns announces Spector's death on television and, in the same statement, thanks Gibson and resigns; Operation Musicman is wound up. The series closes with Gibson back in London, alone, the twenty-pound note Kiera Sheridan gave Spector up on her refrigerator door, intercut with Rose Stagg reading The Frog Prince to her daughter and telling her that is not how the story really goes.

The interrogation is the season's best-acted scene and the one place the two leads face each other as equals; the Vulture recap called the finale one that rests entirely on Gillian Anderson. The weakness is the ending: Spector's suicide denies the story the trial it has spent six episodes building towards, and critics who wanted that reckoning found the finale an anti-climax, The Guardian's Stuart Heritage the most hostile. Opinion divided sharply, Digital Spy calling it a horrific, unexpected ending and Forbes a whimper, and Dornan's shift from grieving amnesiac to open violence split reviewers. Rotten Tomatoes scores the series at 64 per cent and Metacritic at 60, indicating mixed or average reviews. Spector ends the programme dead by his own hand, in a death that echoes both his mother and his victims, and Gibson returns to London, leaving the door open for the character but ending the killer's.