Sirens

After finding a document at the scene of one of the assaults, Jay follows up on the lead, narrowing in on the suspect; forensics uncovers some surprising evidence.

The Serious Crime Group believes a serial rapist is on the loose, but there's no evidence yet; Jay's sister, Ali, moves to London with her new boyfriend Oliver; later, some uncovered CCTV evidence seems to point the finger at Ali's boyfriend.

A series of attacks on lone women walking home in Islington leads the Serious Crime Group to believe that a serial rapist is on the loose.

Jay follows up on the theory that a suspect could be the man they are looking for, and when bank statements confirm that the payslip found at the scene of one of the assaults belongs to him, Wilson organizes an arrest.