Aggregated News

The New York City medical examiner’s office is undertaking an unusual review of more than 800 rape cases in which critical DNA evidence may have been mishandled or overlooked by a lab technician, resulting in incorrect reports being given to criminal investigators.

 Supervisors have so far found 26 cases in which the technician failed to detect biological evidence when some actually existed, according to the medical examiner’s office. In seven of those cases, full DNA profiles were developed — in some instances, evidence that sex-crime investigators did not see for years, hampering their ability to develop cases against rape suspects.

In one of those instances, the newly discovered DNA profile matched a convicted offender’s sample, leading to an indictment a decade after the evidence was collected, according to Dr. Mechthild Prinz, the director of forensic biology at the medical examiner’s office.

In two other instances, the new DNA profiles were linked to people either already convicted or under suspicion.

The scope of the problem has yet to be determined; at several points over nearly two years, supervisors in the medical...