Because the department and the FBI didn't immediately alert state authorities that convictions might be called into question, prosecutors had no reason to consider delaying an execution, the report said.
The report was the inspector general's third since 1997 on irregularities at the main FBI lab, where scientists examine crime-scene evidence.
After one scientist complained 20 years ago that some staffers at the lab were fabricating evidence and reaching conclusions unsupported by science, the Justice Department created a task force to look into the problem and identify cases that needed further review. The new report focused on the task force's work between 1996 and 2004.
The task force reviewed more than 7,600 cases that involved the 13 crime lab examiners, but did not prioritize death penalty cases or treat them all the same way, the report said. That inconsistency showed "the inattentiveness of everyone involved in the process and a lack of focus on the need to treat those cases with urgency," the report said. It added that the department had understaffed the task force and improperly limited its review by excluding whole categories of cases, including those before 1985 or those in which the defendant had died or had a conviction overturned.
The FBI identified more than 60 death-penalty cases handled by at least one of the examiners, but there's no evidence that local prosecutors or prisoner advocates were notified that convictions in their states might be problematic, the report said.
The report recommended that states allow FBI retesting of physical evidence for 24 death row defendants who were executed or who died in prison while on death row. Lawyers for another 26 defendants who are on death row or awaiting resentencing should be notified of the possibility that their convictions were based on unreliable science, the report said.
The Justice Department agreed with the report's recommendations and is taking steps to implement them.