Perhaps the most dramatic example of a massive scandal that cannot seem to be reversed involves Annie Dookhan, a chemist who worked at a Massachusetts state lab drug analysis unit. Dookhan was sentenced in 2013 to at least three years in prison, after pleading guilty in 2012 to having falsified thousands of drug tests. Among her extracurricular crime lab activities, Dookhan failed to properly test drug samples before declaring them positive, mixed up samples to create positive tests, forged signatures, and lied about her own credentials. Over her nine-year career, Dookhan tested about 60,000 samples involved in roughly 34,000 criminal cases. Three years later, the state of Massachusetts still can’t figure out how to repair the damage she wrought almost single-handedly.
http://www.slate.com/articles/news_and_politics/crime/2015/10/massachusetts_crime_lab_scandal_worsens_dookhan_and_farak.single.html