| 1 | Nicholas |
Cresswell | Firm owner. Aka: Nick |
| | Tom |
Thorne | Detective Inspector; protagonist |
| | Dave |
Holland | Thorne's colleague; Detective Inspector |
| | Russell |
Brigstocke | Detective Chief Inspector |
| 2 | Christopher |
Tully | One of the victims |
| | Asim |
Hussain | One of the victims |
| | Kazia |
Bobak | One of the victims |
| | Catherine |
Holloway | One of the victims |
| | Nicola |
Tanner | Thorne's partner; Detective Inspector |
| | Dipak |
Chall | Detective Sergeant |
| | Charita |
Desai | Detective Constable |
| | Jeremy |
Walker | Wood Green Detective Chief Inspector |
| | Stephen |
Pallister | New member of the Major Investigation Team |
| | Craig |
Knowles | Rapist police officer |
| 3 | Phil |
Hendricks | Thorne's friend |
| 4 | Fiona |
| Tanner's girlfriend |
| | Greg |
Hobbs | Member of the Digital Forensics Unit |
| 5 | Helen |
Weeks | Thorne's live-in partner |
| | Alfie |
| Helen's son |
| 6 | George |
Oldfield | Detective in the Yorkshire Ripper investigation |
| 8 | Chris |
Holloway | Catherine's husband |
| 9 | Pippa |
Holland | Dave's wife |
| | Steve |
Pallister | Police officer |
| 11 |
Adam | Callaghan |
Victim |
| | M. |
Healey | Police constable at Callaghan's crime scene |
| 13 |
Karen | Sadler |
Family liaison officer |
| | Daniel |
Sadler | Karen's husband; victim |
| 14 |
LoveMyBro | |
Computer hacker |
| 16 |
Nathan | Sadler |
Karen's son |
| 17 |
Emily | Mead |
Woman who found Callaghan's body |
| 20 |
James | Greaves |
Detective Inspector; Walker's colleague |
| 23 |
ButterflyGrrrl | |
Emily's dark web username |
| | Charita |
Desai | Detective Sergeant |
| | Stuart |
Needham | Security guard; hit-and-run victim |
| 25 |
Sylvia | Holloway |
Catherine's mother |
| 28 |
Martin | |
Father of LoveMyBro |
| | Diane |
| Mother of LoveMyBro; Martin's wife |
| | Peter Samuel |
Brightwell | Convicted rapist |
| 29 |
Siobhan | Brady |
Peter's victim |
| | Alex |
Brightwell | Peter's brother; possible identity of LoveMyBro |
| 30 |
Paul | Hopwood |
Alfie's biological father; police officer |
| 32 |
Merle | Haggard |
American singer and songwriter |
| 33 |
Chowdhury | |
Thorne's colleague |
| 37 |
Priya | Kulkarni |
Craig's rape victim |
| 39 |
Mandy | Brightwell |
Peter's wife |
| 40 |
Andre | Campbell |
Peter's cellmate |
| 45 |
Matt | Parkinson |
Employee at Fin-Cel |
| 55 |
Chloe | Holland |
Dave's daughter |
| 56 |
Sally | Brigstocke |
Russell's wife |
| | Liam |
| Phil's boyfriend |
| 62 |
Patrick | Mead |
Emily's brother |
| 66 |
Bryony | |
Humanist celebrant |
