Responding to the error over the misread lab report, District Attorney Risa Vetri Ferman last month created two new positions within her office to try to prevent such mistakes from happening again. She said she would hire or appoint a deputy district attorney for professional standards to lead independent case reviews for other members of the office. A second new position, assistant chief of trials, will oversee the investigations and prosecutors in that division. That post has already been filled by Assistant District Attorney Jesse King, she said.