Though DNA evidence gets all the glamor in TV crime shows, it is new eyewitnesses who more often help solve cold cases, a study finds.
In the study, the team looked at the factors linked to successful convictions in 189 cold case investigations from the files of the District of Columbia's Metropolitan Police Department. The homicides dated back to the 1970s, but most had occurred in the past two decades.
Of those reopened cases, 24 percent ended in convictions and another 24 percent were successfully closed due to "instances in which the culprit was already dead, in prison, or had gone missing," Discover reports.
Of those solved cases, 63 percent were cleared because new witnesses came forward. DNA was involved in just 3 percent of the cracked cases.
But witness testimony can often prove faulty, according to the Sentencing Project, an organization committed to exonerating people who have been falsely convicted.
Research conducted by and referenced by the Sentencing Project has found:
• Over 230 people, serving an average of 12 years in prison, have been exonerated through DNA testing in the United States, and 75% of those wrongful convictions (179 individual cases as of this writing) involved eyewitness misidentification.
• In 38% of the misidentification cases, multiple eyewitnesses misidentified the same innocent person;
• Over 250 witnesses misidentified innocent suspects;
• Fifty-three percent of the misidentification cases, where race is known, involved crossracial misidentifications;
• In 50% of the misidentification cases, eyewitness testimony was the central evidence used against the defendant (without other corroborating evidence like confessions, forensic science or informant testimony).
• In 36% of the misidentification cases, the real perpetrator was identified through DNA evidence;
• In at least 48% of the misidentification cases where a real perpetrator was later identified through DNA testing, that perpetrator went on to commit (and was convicted of) additional violent crimes (rape, murder, attempted murder, etc.), after an innocent person was serving time in prison for his previous crime.