Why is identification evidence unreliable

By the same token, DNA evidence is largely viewed as unassailable, in part because of its publicized role in overturning wrongful convictions. But in reality, DNA evidence can be unreliable in the same way that eyewitness-identification evidence can be unreliable — namely, when the evidence is contaminated. Because DNA evidence generally is regarded as the gold standard of forensic evidence, I decided to use that as my example. The story begins with a tragic event: year-old University of Michigan law student Jane Mixer was shot in the head with a.

She had arranged to meet a stranger named David Johnson at the student union on the evening of March 20, , and he was supposed to drive her home to Muskegon, Michigan about a 3-hour drive. She never made it. That analysis uncovered two previously undetected DNA profiles that matched the profiles of two men who were included in a federal DNA database because they had recently committed crimes.

One of those men was John Ruelas, who murdered his mother in early The other was Leiterman, who recently had forged a prescription for pain medication. His DNA was found on a piece of pantyhose that Mixer had been wearing that day. Because Ruelas was only 4 years old in , he was ruled out as a suspect, so only Leiterman remained a suspect.

In , he was sentenced to life in prison without the possibility of parole. The discovery of DNA from Ruelas on the Mixer evidence should have been seen as an indication of potential contamination problems.

Instead, the prosecution posed the theory that Leiterman killed Mixer and left his DNA at the crime scene in and that 4-year-old Ruelas also was there and somehow left a drop of blood on Mixer. No connection between Leiterman and Ruelas has ever been established.

To this day, Collins is widely believed to have murdered at least seven women between and , and he was convicted in for one of those murders. According to the defense, the Mixer evidence likely was contaminated with DNA from both Ruelas and Leiterman, and it was the obvious suspect, Collins, who committed the crime.

The timing of the DNA analyses is striking Fig. On October 24, , the Mixer evidence from was pulled out of storage and taken to the Michigan State Police crime lab for processing.

It was analyzed in March and April of Independently, evidence from the Ruelas murder case arrived at the lab on January 29, , and was analyzed on February 20 and 21, On February 22, , a mouth swab from Leiterman arrived in the lab for initial processing so that his DNA profile could be entered into the federal database.

The possibility of contamination looms particularly large in light of the improbable Ruelas DNA evidence. Moreover, the evidence from the three different cases was analyzed in different physical locations in the lab on different days, thereby rendering cross-contamination even from unnoticed and thus unrecorded events a virtual impossibility, in their view. To many observers, myself included, it is an inconceivable set of coincidences. Rasheen Mahmodian. Barristers We Instruct.

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Criminal Legislation Read relevant sections of the Act under which you are charged. For example, Figure 1 from a study by Jesse Grabman and colleagues presents results from an experiment evaluating the accuracy of identifications that were made with different levels of confidence and with different speeds. The top line in Figure 1 shows that participants who expressed the highest level of confidence in an identification of a face from a lineup were nearly 95 percent accurate when the identification occurred within a few seconds.

However, the accuracy of these highly confident identifications dropped to nearly 75 percent when decision times took roughly 10 seconds. Accuracy approached 50 percent for even longer decision times. See Figure 1 — identification accuracy as a function of confidence-level and decision-time. Error shading represents 95 percent confidence intervals. Many of us have had the embarrassing experience of either mistaking a stranger for an acquaintance or failing to recognize someone we just met the day before.

Face-recognition ability varies greatly from person to person — from super-recognizers to individuals who are face-blind. Over the course of 72 progressively more difficult trials, participants attempt to recognize the correct face from three similar-looking alternative faces.

The overall sum of correct responses on this task is a highly reliable measure of face-recognition ability. It found extensive variability across individuals and also noted that face-recognition performance peaks at around the age of With respect to eyewitness-identification performance, stronger face-recognizers tend to be more accurate than weaker face-recognizers. Cross-race identifications are disproportionately related to false convictions.

By using Caucasian-face and Asian-face versions of the CFMT, Lulu Wan and colleagues showed that the cross-race recognition impairment effect greatly depends on face-recognition ability.

The cross-race effect is nearly nonexistent in stronger face-recognizers, but it is substantial in weaker face-recognizers. There are a number of reasons why visual identification evidence is not reliable including:. Other types of identification evidence such as fingerprint evidence and DNA evidence are considered more reliable. This warning is a cautionary instruction and must state:. The witness should be shown photographs of many possible suspects. If a witness identifies a suspect using photographs and the prosecution wants to put this evidence to the jury, the defence counsel can challenge this with the judge in the absence of the jury.

The judge will decide whether this evidence should be put to the jury. They are not really used in criminal trials as they are not considered to be real evidence , unlike a photograph or video. This means that they would not be valued as identification evidence in court. Perhaps the best way to describe them is as an aid to a criminal investigation.