Sagan
| Played by | James Michael Reilly |
| Name | W. Sagan |
| Status | Alive |
| Occupation | Police Detective |
| Residence | New York, NY, U.S. |
| Affiliation | NYPD HR |
| First appearance | “Firewall” |
Detective W. Sagan is a detective with the NYPD.
He is present in the RTCC when the FBI including Special Agent Nicholas Donnelly close in on Reese.
He is secretly feeding intel to Simmons so that he can direct his team of hitmen chasing Caroline Turing, who is on the run with Reese.
Fusco, working undercover in HR for Reese, is aware of Sagan's identity as the mole and after the manhunt fails, sends pictures of Sagan meeting with HR's Inner Council to Donnelly. Sagan is then arrested by Donnelly for his actions.