Contesting eyewitness testimony in Pennsylvania criminal cases

When people in Lehighton face criminal charges, the testimony of an eyewitness who observed the alleged crime can seem like compelling evidence. This is especially true for intimate or violent crimes, such as assault, rape or murder. However, as many people know, the way that humans observe and interpret events is not always perfect, and human memory is far from infallible. For these reasons, eyewitness evidence may be worth challenging in many criminal cases.

Unreliable evidence

According to Newsweek, research shows that human memories can be lost, altered or completely invented without a person realizing any changes have occurred. Outside influences, including interviews with law enforcement authorities, sessions with therapists and media reports, can cause a person to change or fabricate a memory. Humans also naturally fill in gaps in their memories based on outside beliefs or experiences. All of these factors can reduce an eyewitness's accuracy.

Certain situations increase the likelihood of eyewitness errors even more. According to the Innocence Project, if lighting is poor or if an eyewitness views an alleged crime from a greater distance, the risk of mistakes rises. The following factors also make an inaccurate memory or false identification more likely:

  • Stress - after traumatic or stressful incidents, such as robbery, assault or other alleged physical contact, eyewitnesses are less likely to accurately remember the alleged offender's appearance.
  • Weapon use - the presence of a weapon can enhance stress and distract an eyewitness from the alleged perpetrator's face.
  • Racial disparities - eyewitness are also more likely to make bad identifications when the suspect has a different racial background.

The risk of eyewitness inaccuracy isn't trivial. Since 1989, eyewitness mistakes have contributed to 72 percent of the wrongful convictions that have since been overturned in light of DNA evidence.

Addressing eyewitness errors

Newsweek states that some states, such as New Jersey, now instruct juries on the potential limitations of eyewitnesses and the factors known to contribute to poor identifications. Other states, such as Oregon, consider the validity of eyewitness testimony; evidence based on leading questions or questionable tactics may not be permitted in court. While Pennsylvania has not taken these steps, the state Supreme Court recently ruled that experts who are familiar with the inherent issues with human memory can testify during criminal trials.

According to The Pittsburgh Post-Gazette, in 1995, the Pennsylvania Supreme Court ruled against allowing this testimony on the grounds that cross-examination of eyewitnesses can reveal issues with accuracy. Critics of the ruling worried that cross-examination isn't necessarily effective if an eyewitness genuinely believes in what he or she is saying. The new ruling was made because various issues with eyewitness testimony, regardless of the eyewitness's intentions, have been scientifically established over the last two decades.

Using an expert witness or other tactics to highlight the limitations of eyewitness evidence may make a significant difference in the outcome of some criminal cases. Anyone facing criminal charges based on eyewitness testimony should speak with an attorney who knows how to ensure that all relevant facts in the case are considered.