New York (CNN) -- A review of forensic evidence in New York City rape cases has uncovered 26 incidents where critical evidence went undetected, prompting the city's medical examiner's office to look into more than 800 rape cases over 10 years, "reviewing and retesting everything."
On Friday, the medical examiner's rape-case review prompted New York's City Council speaker to set an "emergency oversight hearing" for January 22.
"The mishandling of rape cases is making double victims of women who have already suffered an indescribably horrific event," City Council Speaker Christine Quinn said. "We cannot allow these women to wonder if their attacker remains free or to go one more day without knowing justice was served in their case."
The review, which began in July of 2011, focuses on the work of one technician includes all cases the technician processed over a 10-year period.
So far, that re-examination has uncovered 26 cases where the technician allegedly failed to detect biological evidence critical to the cases. In another 19 cases, the review found that pieces of evidence were in the wrong rape kits.
'"The only answer here is a top-down, complete review on how they train, the procedures they use and the oversight," said Sonia Ossorio, president of the National Organization for Women of New York City. "The mishandling of evidence can mean that rapist who should be in jail are out walking the street just looking for more victims."
The results have only indicated false negatives, not false positives, according to Chief Medical Examiner spokeswoman Ellen Borakove.
"We know that nobody has been wrongfully convicted, and nobody is serving time for something they shouldn't be serving time for," she said.
The technician in question was in charge of processing rape kits, alongside some 40 other staff members at the office.
Around the end of 2008-2009, after she enrolled in a training program to become a DNA analyst, the supervisors realized "there was a problem" and took her off casework, Borakove said.
Her mistakes then prompted supervisors to look at her earlier work,and they discovered the false results.
"She (the technician) is no longer here and that's the important thing," said Borakove.
The newly discovered forensic evidence has since led to the indictment of a Brooklyn man in an incident 10 years earlier, according to Borakove and the district attorney's office.