A vigilante is on the loose on the upcoming episode of "Chicago P.D." season 5.

Titled "Sisterhood,"  this week's episode will see Intelligence work on a case involving a vigilante. They must track down an individual suspected of killing rapists. Meanwhile, the investigation hits too close to home for Burgess (Marina Squerciati). While searching for new leads, she remembers her sister's assault and questions if her attackers truly paid for their actions.

Fans can remember in season 4 that Nicole Silver (Jules Wilcox) went to Chicago to visit her sister, Burgess. While strolling around the city, she was raped and beaten by a stranger. The perpetrator was arrested and Burgess took some time off to be with her sister.

Future episodes will also explore Hank Voight's (Jason Beghe) dark past. Bingham's (Joseph Sikora) body was recently discovered and independent auditor Denny Woods (Mykelti Williamson) will stop at nothing until he finds answers. Speaking with TV Guide, showrunner Rick Eid said Voight will continue to fight for justice despite the storm of consequences that haunt him.

"Voight has an interesting constitution as a cop and as a man. He's always trying to get the bad guy. That will never change," Eid teased.

In other news, a familiar face is heading to "Chicago P.D." later in season 3. "The Good Wife" alum Titus Welliver has been tapped to play meth dealer Ronald Booth in the show's upcoming episode 18. After being released from prison, Welliver will return to his old ways and cross paths with Intelligence.

Aside from his current role on the Amazon Prime drama "Bosch," Welliver is also known for playing the Man in Black on "Lost." He has also played roles in "NYPD Blue," "Deadwood," "The Last Ship," "Marvel's Agents of S.H.I.E.L.D." and "Sons of Anarchy." His most notable big screen projects include "Argo," "The Town," "Live by Night," "Transformers: Age of Extinction" and "Red 2."