S4·E2 The Two Faces of Betsy Morgan

Hooker and Romano by chance spot a van swerving dangerously over the road – in which a pair of teenage prostitutes are being held against their will by two men. When the van crashes off the road, they find one of the girls dead after being strangled – the latest victim in a series of killings by ""The Boulevard Strangler"" and his accomplice, who are prying on young runaways. Hooker finds that the surviving girl has run away after being abused at home, and leads a double life – a perfect high-school student, and as a prostitute. But now the girl is in danger with the killers after her, who are concerned that she can identify them in the murder of the other girl... Meanwhile, Corrigan considers leaving the force to take a job teaching.