(CNN) -- A former Massachusetts state chemist accused of misconduct in thousands of criminal cases was arraigned in two different courts Wednesday on additional charges relating to her alleged false claims about holding a master's degree in chemistry.
In the morning, Annie Dookhan, 34, of Franklin, Massachusetts, pleaded not guilty to three counts of obstruction of justice in Middlesex Superior Court in Woburn, Massachusetts. Her next court date there is February 8 for a pre-trial conference.
In the afternoon, she again pleaded not guilty to two counts of obstruction of justice in Norfolk Superior Court in Dedham, Massachusetts. She was released on her personal recognizance and is scheduled for another pre-trial conference there in February.
In December, Dookhan was indicted in Suffolk County in Boston on charges relating to alleged mishandling of evidence and obstruction.
Massachusetts authorities are reviewing the sentences of 1,140 people who are in prison after being convicted with evidence at least partly provided by Dookhan.
She is facing charges in several counties in Massachusetts because she had previously testified in various trials in her former official capacity as a chemist.
In October, police arrested the former chemist on accusations that she had lied about drug evidence she handled while working at a state police lab and pretended to hold a master's degree in chemistry from the University of Massachusetts.
She allegedly "lied about the integrity of drug evidence that she analyzed," the attorney general said in a statement last year.
The former chemist has admitted to wrongdoing during her nine-year employment with the Department of Public Health.
A preliminary investigation looked into every case Dookhan may have touched from 2003 until she left last March, and it is possible she touched 60,000 samples that were involved in 34,000 drug cases.
"There will be designated court sessions in each county to hear the cases," Chief Justice Robert Mulligan said last October in a statement. "The Trial Court is fully cooperating with the prosecutors and defense counsel who are responding to these issues."
State police were tipped off last July by Dookhan's co-workers at the William A. Hinton State Laboratory in Jamaica Plain who alleged her work might be unreliable.
At the time, state police were taking over what had previously been a Department of Public Health drug laboratory, which certified random drug tests for the police departments in Norfolk, Suffolk, Middlesex and Bristol Counties, as well as for Cape Cod and the nearby islands.
During the takeover, authorities learned from employees how they were afraid to verify the work of Dookhan, said a spokesman for the Executive Office of Public Safety and Security.
Dookhan worked as a chemist in the Hinton State Lab's drug analysis unit -- which tested drug evidence submitted by law enforcement agencies across the state -- from 2003 until last March, when she resigned, according to a statement last month by Massachusetts attorney general's office.
She was promoted from chemist I to chemist II in 2005.
Her work was "consistently the highest in the lab among her co-workers" until June 2011, when an evidence officer discovered that 90 samples of drugs had been improperly "scanned out of the drug safe" and that Dookhan's name appeared on the control card as the primary chemist, the attorney general's office said.
"The next day, when Dookhan was confronted with the log book, the initials of Gloria Philips had suddenly appeared in the book," the attorney general's statement said. Phillips was an evidence officer, according to the statement.
Dookhan denied writing the initials at first, but she "later confessed to investigators" that she forged them "to cover up her misconduct," the statement said.
Last July, Massachusetts State Police investigators interviewed lab employees. On August 28, Dookhan "admitted to 'dry labbing' some of the samples," the statement said.
"Dry labbing" is the practice of merely visually identifying samples instead of performing the required chemical test, the attorney general said.
"It was discovered that Dookhan would assemble multiple drug samples from different cases that appeared to be the same substance. She would then perform the chemical tests on a few of the samples to verify that the samples were in fact the drug she believed they were, and if those were positive, would assume all the samples were positive without performing the necessary chemical tests," the attorney general said.
Massachusetts Gov. Deval Patrick ordered the lab to be shut down on August 30.