Prosecutors in Colorado and around the country often ask forensic scientists to present evidence in criminal trials because they know that juries find their testimony compelling. While scientific techniques like fingerprint and DNA analysis are based on solid science and extensive research, other forensic approaches like 911 call and blood spatter analysis are the product of what experts refer to as junk science. These techniques appear to bear all of the hallmarks of established science, but there is little evidence or data backing them up.
911 call analysis
People who analyze 911 calls are trained to find guilt indicators like unusual pauses or speech patterns. The approach was pioneered by a retired police chief with no scientific credentials and very little experience in homicide cases. Since 2006, 911 call analysts have assisted detectives in thousands of homicide investigations and presented evidence in hundreds of criminal trials. The approach was originally endorsed by the FBI, but researchers have failed to find any evidence to suggest that it actually works. In 2022, an FBI study concluded that 911 call analysis was unreliable and could actually increase bias. The approach is now considered to be junk science.
Blood spatter analysis
Forensic scientists and police officers who have been trained to analyze blood spatter claim that the blood trails and drops found at crime scenes can be used to determine what happened, but the approach is based almost entirely on the work of a single criminologist. The accuracy and reliability of blood spatter analysis has never been established by experts, and the practice was harshly criticized by the National Academy of Sciences in a watershed 2009 report. In the years since that report was published, criminal defense attorneys in several parts of the country have overturned convictions that were based largely on the testimony of blood spatter analysts.
More rigorous standards are needed
Novel forensic approaches like 911 call and blood spatter analysis are usually embraced by police officers and prosecutors, but research conducted by experts often reveals that they are really little more than junk science. The scientific evidence presented in criminal trials should be beyond reproach, which is why more rigorous standards are needed to weed out junk science and unproven theories.
