20 Apr 2017 05:57 PM EST

in what is believed to be the single largest dismissal of wrongful convictions in US history, Massachusetts’ high court has dismissed 21,587 drug cases. The dismissals bring closure to a five-year legal battle waged by the ACLU of Massachusetts. The battle came after it was revealed that former state chemist Annie Dookhan tampered with and fabricated lab evidence in thousands of cases. Dookhan worked at Hinton State Laboratory between 2003 and 2011. Dookhan pleaded guilty in November 2013 and was sentenced to three to five years in prison.