This week, the FBI and US Department of Justice released the results of an ongoing review of thousands of potentially wrongful convictions, based on their scientists’ testimonies. The FBI’s forensic methods of the 1980s and 1990s involved looking at hair samples under the microscope, without the mitochondrial DNA testing included with this type of analysis today. The New Scientist explains:

Two years ago, the FBI launched an inquiry into 2600 convictions, including 45 death-row cases, from the 1980s and 1990s, looking for instances where FBI analysts may have exceeded the limits of science when presenting their conclusions in court – saying a hair matched to the exclusion of all others, for example, rather than simply saying it looked similar.

A genetic match vs. superficially “similar”? That’s quite an unscientific difference.

Only 10% of these cases have been reviewed so far, and already it has been determined that the “vast majority” of forensic conclusions contained errors. A total of 136 defendants will soon be informed of their right to be DNA tested to prove their possible innocence. Two of these defendants are currently on death row.