| 1 | Joseph | Halsted | Vienna detective.
Detective in Laura Berg's case. Aka: Joe. |
| | Martin | C. Wagner | The Serial Killer. Aka: Charlie, Lew, Darwin. |
| | Emily Jean | Dockery | The FBI data analyst. Protagonist. Aka: Emmy. |
| | Laura | Berg | One of Charlie's victims. |
| 2 | Nora | Connolley | Deceased. Victim. |
| | Nigel | Flowers | The spokesman of New Orleans police department. |
| | Dorian | Dockery | Emmy and Martha's mother. |
| 4 | Harrison | Bookman | Emmy's fiancé. Aka: Books. |
| | Petty | | A homeless man. Books' friend. |
| | William | Moriarty | The FBI director. Aka: Bill. |
| | Desmond | | Bill's head of security. Aka: Dez. |
| 6 | Robert | Crescenzo | New Orleans detective.
Detective on Nora Connolley's death. |
| | Graham | | The arsonist. |
| 8 | Mary | Connolley | Nora's daughter. |
| | Sarah | Connolley | Nora's daughter. |
| | Michael | Connolley | Nora's son. |
| 10 | Lee | Homer | A special agent from FBI's tactical unit. |
| 13 | Nadia | Jacobius | A reporter at Times-Picayune. |
| 15 | Dwight | Ross | FBI director of criminal, cyber, response, and service branch. |
| | Lydia | | Emmy's co-agent. |
| | Denny | | Emmy's co-agent. |
| | Sophie | | Emmy's co-agent. |
| 16 | Citizen | David | A domestic terrorist. |
| | Shaindy | Eckstein | The writer for FBI's Citizen David's hunt. |
| 17 | Dr. | Bakalis | Emmy's therapist. |
| 18 | Roberta | | Dwight Ross's receptionist. |
| | Carlton | | The FBI agent from national security branch. |
| | Sloan | | The FBI agent from criminal investigative division. |
| | Cobbs | | The FBI agent from science and technology department. |
| 28 | Betsy | Moriarty | Bill's wife. |
| 33 | Bonita | Sexton | Emmy's teammate in Citizen David case. Aka: Rabbit. |
| | Eric | Pullman | Emmy's teammate in Citizen David case. Aka: Pully. |
| 34 | Elizabeth | Ashland | The FBI's special assistant director. Aka: Lizzie. |
| 35 | Michelle | Fontaine | Tom's partner. |
| | Tom | Miller | Michelle's co-therapist. Charlie's therapist. Aka: Todd Crisman. |
| | Mrs. | Person | One of Tom and Michelle's patients. |
| | Mr. | Oakley | One of Tom and Michelle's patients. |
| | Mrs. | Coxley | One of Tom and Michelle's patients. |
| 37 | Mayday | | A homeless man. Aka: Marlon Mayberry. |
| 43 | | | TATP - Triacetone Triperoxide. |
| 44 | Wilson | | The assistant special agent in-charge in Chicago. |
| | Ron | Sims | The security guard at Cash4u Quick. |
| | Alice | Jagoda | The utility at Cash4u Quick. |
| | Acevedo | | Alice's partner. |
| | McBride | | A CPD officer. |
| | Natalie | Ciomek | A CPD officer. |
| | Gordon | | A CPD officer. |
| 50 | Sperry | | Mayday's friend. |
| 65 | Olympia | Janus | The FBI's forensic pathologist. Aka: Lia |
| 66 | | | COPD - Chronic Obstructive Pulmonary Disease. |
| 87 | Amee | Czernak | The top prosecutor. |
| 97 | | | CSLI - Cellphone Site Location Information. |
| | | | ALPR - Automatic License Plate Reader. |
| 99 | Louise | | Tom's administrator. |
| 101 | Steven | Macdaniel | One of Charlie's victims. |
| 105 | Rich | Rudney | The lead agent on the forensic team. |
| 117 | Jordan | Sexton | Rabbit's son. |
| | Mason | Sexton | Rabbit's son. |
| 118 | Mary Ann | Stoddard | Petty's sister. |
| 119 | Hendrick | | One of the FBI agents. Books'
acquaintance. |
