The director of the embattled D.C. Department of Forensic Sciences is stepping down. Dr. Jenifer Smith, who was appointed to run the lab by Mayor Muriel Bowser in 2015, submitted her resignation to the mayor Wednesday, amid rising calls from District officials for her to step aside. Under Smith’s watch, the forensic lab came under increasing scrutiny following the discovery of a series of errors in the crime lab’s Firearms Examination Unit, a turn of events that eventually led to an ongoing criminal investigation and the withdrawal of the lab’s accreditation to perform a wide range of forensic testing earlier this spring.