BOSTON — A former chemist at a Massachusetts drug lab who admitted faking test results in criminal cases pleaded guilty Friday and was sentenced to prison in a scandal that has jeopardized thousands of convictions.
Annie Dookhan changed her plea Friday in Suffolk Superior Court on charges of obstruction of justice, perjury and tampering with evidence. She was sentenced to three to five years in prison, followed by two years’ probation.
The diminutive Dookhan did not address the court. She answered “guilty” and replied to a series of routine questions from the judge in a barely audible voice. She was led away in handcuffs and will begin serving her sentence immediately at the state women’s prison in Framingham.
Dookhan sent the state’s criminal justice system into a tailspin last year when state police shut down the state Department of Public Health lab she worked at after discovering the extent of her misconduct.
Prosecutors said Dookhan admitted “dry labbing,” or testing only a fraction of a batch of samples, then listing them all as positive for illegal drugs, to “improve her productivity and burnish her reputation.”
Since the lab closed in August 2012, at least 1,100 criminal cases have been dismissed or not prosecuted because of tainted evidence or other fallout from the lab’s shutdown.
Anne Kaczmarek, the state’s prosecutor, asked Judge Carol Ball to impose a five- to seven-year sentence, citing the “egregious nature” of Dookhan’s actions. Ball had already said in a written memo that she would not sentence Dookhan to more than three to five years if she changed her plea.
Defense attorney Nicolas Gordon asked for a one-year sentence for his client, who has no previous criminal record.
Prosecutors said Dookhan’s actions had caused serious damage to the criminal justice system and cost the state millions of dollars to assess the damage and mitigate the effect on thousands of people charged with drug offenses during the nine years Dookhan worked at the lab. The court system has been flooded with motions for new trials filed by defendants in drug cases.