Washington ( CNN ) -- The FBI and Justice Department are undertaking a broad review of thousands of criminal cases to see if any defendants were wrongly convicted based on faulty forensic analysis . An FBI official said Thursday the issue is whether in some cases FBI experts went too far in trial testimony and drew more conclusions than existing scientific techniques could support . `` The department and the FBI are in the process of identifying historical cases for review where a microscopic hair examination conducted by the FBI was among the evidence in a case that resulted in a conviction , '' said Justice Department spokeswoman Nanda Chitre on Wednesday . `` We remain committed to working closely with our law enforcement partners to go through thousands of cases , all of which are more than a decade old , and to assemble evidence for purposes of conducting a thorough and meaningful review of convictions . '' Convictions and corrections : A look at the numbers behind wrongful imprisonment . The Washington Post first reported the review . This follows a report by the newspaper in April that Justice officials had known for years that questionable forensic work might have occurred in some trials in which defendants were convicted , but that no new look at the cases had taken place , and that defendants and their lawyers had not been informed of possible problems in the evidence . The review will include cases in which the FBI lab was involved . In addition to analyzing evidence in federal cases , the lab provides assistance to state and local law enforcement agencies . FBI forensic examiners have testified in trials throughout the country . The FBI has been able to provide more thorough analysis of small or degraded hair sample evidence since it began using mitochondrial DNA testing in 1996 . On Tuesday , federal prosecutors in Washington said a man convicted of a 1981 rape and home invasion is innocent and his conviction should be vacated . Kirk Odom , 49 , spent 22 years in prison and was released in 2003 . His case was highlighted by the Washington Post in April as one involving faulty forensic analysis . The U.S. attorney 's office for the District of Columbia said recent DNA testing in the case proved Odom was not the culprit . Instead , it said , the sample matched another man in the FBI 's Combined DNA Index System who had previously been convicted of a sex crime . That person will not be charged in the 1981 rape because the statute of limitations has expired . The Justice Department did not estimate how long it will take to go through cases or how many total cases may be reviewed . Officials said they will work on the review with two independent groups , the Innocence Project and the National Association of Criminal Defense Lawyers . County settles for $ 4.1 million in wrongful imprisonment suit .
The review is looking for defendants wrongly convicted based on faulty forensic testimony . The action follows a Washington Post report that the Justice Department knew of problems . The Justice Department did not estimate how long it will take to go through cases .