Originally Posted by
Dr Cross
The Case
Steven Murphy was accused of sexually assaulting a woman (Linda Byrne) on the night of January 8, 1994. The sexual assault occurred in the stairwell of Linda Byrne's apartment building as she was walking up to her apartment from the parking garage.
The prosecution alleges that Steven Murphy hid between two cars in the parking garage, waiting for a lone woman to walk by. When he saw Linda Byrne walking alone towards the stairs, he came out and followed her. When she entered the stairwell, he grabbed her from behind, held a large knife to her throat, and sexually assaulted her. She did not get a look at his face because he was wearing a mask, although it became partially removed during the attack.
The defense contends that the police charged Steven Murphy with the crime because they were too lazy to conduct a more thorough investigation. The defense alleges that the sexual assault was most likely committed by a serial rapist who had been operating in the area near where Linda Byrne lived for the past several months.
Linda Byrne was taken to a hospital for a medical examination, which revealed that she suffered injuries that were consistent with forced sexual intercourse (i.e. rape). The medical examiner also found several fresh semen stains, as well as blood stains and hair fibers on her clothing, and fingerprints on her glasses, that were collected and preserved as evidence.
About 45 minutes after the attack occurred, Steven Murphy was stopped while making an illegal "U-turn" about a mile from Linda Byrne's apartment building. When the Garda (Mark Daley) went to talk to Steven Murphy, he noticed that he had a large knife partially visible in his jacket pocket. Garda Daley arrested Steven Murphy for possession of an illegal weapon (knife with a blade over 4" long) and took him down to the police station.
At the police station, Garda Daley learned that a sexual assault had occurred close to where he had arrested Steven Murphy. When he asked Steven Murphy where he had been during the past few hours, he said he had been "driving around" for a while. He also said that he had been at a bar earlier on, but when asked for the name of the bar, he said that he could not remember it.
At this point Garda Daley decided that Steven Murphy might be a suspect in the sexual assault of Linda Byrne. That same evening, Linda Byrne was shown a police lineup consisting of Steven Murphy and several other men who were about the same height and physical description. Linda Byrne was unable to pick out anyone, and said that although a couple of them looked similar to her attacker, she really didn't get a good enough look at his face to recognize him again.
Question 1
At this point, what would you estimate to be the probability that Steven Murphy sexually assaulted Linda Byrne? Please choose a number between 0% and 100%, where 0% means, "absolutely sure he did not do it" and 100% means, absolutely sure he did do it": _________%