Officials with the New York City medical examiner's office say they've taken measures to correct failures in DNA analysis in rape cases.
The officials spelled out the stricter oversight at a City Council hearing Friday.
The hearing followed news reports that the office was reviewing evidence in more than 800 cases because of sloppy work by a lab technician.
Officials say the review found that there were only two instances where testing failed to identify DNA evidence that could have been used in prosecutions.
The tech has been resigned. One supervisor was fired and another suspended over the errors.
Officials say the office has shaken up its management team and cracked down on underperforming lab techs.