Single mother Betty Dixon has been savagely stabbed to death with a bollo knife. A lack of additional evidence makes it extremely difficult for Friday (Jack Webb) and Smith (Ben Alexander) to locate the perpetrator; all that is certain is that the killer is a madman. Ultimately, the detectives track down a recently discharged mental patient--who insists the victim "dared" him to murder her! This episode was adepted from the Dragnet radio broadcast of August 3, 1950. ~ Hal Erickson, Rovi