Prosecutors want former state chemist Annie Dookhan to spend up to seven years in prison for allegedly mishandling drug samples and obstructing justice in a devastating scandal that has called into question thousands of cases and marred the integrity of the criminal justice system in Massachusetts.
Attorney General Martha Coakley’s office recommended in a court filing Thursday that Dookhan serve five to seven years in prison, followed by a five-year probationary term, if she decides to plead guilty to more than two dozen criminal charges.
Coakley’s office filed the request in response to an order from Suffolk Superior Court Judge Carol S. Ball seeking sentencing recommendations from the prosecution and defense ahead of a conference scheduled for Friday “regarding a possible change of plea” in the case, records show.
Dookhan has pleaded not guilty to the charges, which include evidence tampering and obstruction of justice. Her lawyer, Nicolas A. Gordon, provided a copy of his recommendation to the judge and planned to formally file it on Friday, a court official said.
Each count of tampering with evidence and obstruction carries a sentence of up to 10 years in state prison.
A single perjury count, which Dookhan also faces, carries a sentence of up to 20 years in prison. She is also charged with lying about her educational credentials, which is a misdemeanor and can result in up to 2½ years in county jail.
Neither Gordon nor prosecutors would discuss the possibility of a plea bargain.
The case against Dookhan stems from her actions at the now-closed Hinton state lab in Jamaica Plain, which the Department of Public Health ran during her career, from 2003 to 2012. State Police discovered Dookhan’s alleged wrongdoing after they had taken over the lab.
In their sentencing memorandum, prosecutors said Dookhan deliberately tampered with evidences so that substances would test positive for drugs.
“With no regard for the consequences, the defendant ensured that samples would test positive for controlled substances thus eviscerating both the integrity of the lab’s internal testing processes, and the concomitant fact-finding process that was a jury’s to perform,’’ Coakley’s office wrote.
Prosecutors said the “gravity of the present case cannot be overstated. The defendant’s actions not only affected the particular individuals named in the indictments but also the entire criminal justice system in Massachusetts.”
Boston lawyer David Meier, at the request of Governor Deval Patrick, studied Dookhan’s caseload and concluded earlier this year that her actions may have tainted more than 40,000 cases.
Since last year, the state Department of Correction has released more than 300 men and women serving sentences for drug convictions that involved Dookhan. That number does not include anyone released by a county house of correction.
A recent Globe review of court records showed more than 600 so-called Dookhan defendants have had convictions against them erased or temporarily set aside or have been released on bail pending new trials.
One Dookhan defendant, Donta Hood of Brockton, has been accused of shooting and killing a man in May after being freed.
Suffolk District Attorney Daniel F. Conley, whose office faces the largest number of Dookhan-related cases, endorsed Coakley’s sentencing recommendation on Thursday.
“Annie Dookhan violated her duties as a scientist and a state employee. She betrayed the public’s trust and undermined their confidence in our justice system,’’ Conley said in a statement. “What she did will take many years and many millions of dollars to undo, and there is no question that her actions warrant a significant state prison sentence.”
Suffolk prosecutors have requested or agreed to stays of sentences in about 300 cases, with approximately 65 defendants later admitting their guilt and another 65 or so being rearrested in the county, said Jake Wark, a spokesman for Conley.
Wark said in an e-mail that prosecutors have found “only three cases in which a substance certified as an illegal drug was retested and found not to be a drug. We terminated those cases and an additional dozen or so in which we felt we couldn’t meet our burden of proof.”
While Dookhan’s defense team had not yet formally filed their recommendations, area defense lawyers not involved in the case reacted coolly to the proposed sentencing from prosecutors.
“I never want to advocate for anyone to go to jail,’’ said Boston lawyer Bernard Grossberg, who has represented multiple Dookhan defendants. “But the harm she has done to so many people is incalculable.’’
He said prosecutors should also recommend that Dookhan be compelled to disclose cases that she remembers falsifying test results for, and also that she identify anyone else who engaged in similar behavior.
“Just giving her a prison sentence is not sufficient,” Grossberg said. “She should come clean about everything that went on at the lab. Full disclosure.’’
Dookhan’s work e-mails showed she was highly regarded, both by prosecutors and people inside the drug lab, where she processed more than twice as many drug cases as anyone else, the Globe reported in December.
John Cunha, a Boston lawyer and a former president of the Massachusetts Association of Criminal Defense Lawyers, said Thursday that while Dookhan’s conduct was “outrageous,” he believes she is being scapegoated.
“What’s happening to the supervisors who didn’t seem to make any inquires when she was handling twice, three times as many cases as anybody else?” Cunha said. “They were happy with the convictions. And now that it’s all been revealed, they want to make her the scapegoat, so they can tell the public, ‘we took care of the rogue.’ ”
Rosanna Cavallaro, a Suffolk Law professor and an evidence specialist, also alluded to apparent systemic problems in the lab.
“It really suggests that there must have been some broader . . . neglect that could have allowed this to go undetected,” said Cavallaro, a former assistant attorney general who also worked in the law office of renowned defense lawyer Alan Dershowitz.
At the same time, the prosecutors’ sentencing recommendation speaks to the gravity of the alleged offenses, Cavallaro said.
“The punishment has to clearly signal to everyone who’s watching, and we are, that we cannot tolerate this,” she said.