(CNN) -- Police on Friday arrested a former Massachusetts chemist accused of lying about drug evidence she handled while working at a state police lab, which has raised doubts about thousands of criminal cases.

Annie Dookhan, 34, was picked up by state police at her home in Franklin, Massachusetts, and has been accused of obstruction of justice and pretending to hold master's degree in chemistry from the University of Massachusetts.



She allegedly "lied about the integrity of drug evidence that she analyzed," according to an attorney general statement Friday.

Massachusetts authorities will review the sentences of 1,140 people who are in prison after being convicted with evidence at least partly provided by Dookhan, whose work with criminal evidence is under investigation.

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 in 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 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 in July by Dookhan's co-workers at the William A. Hinton State Laboratory in Jamaica Plain that 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.

"When they were getting ready to take over the lab, they learned through conversations with other employees who were afraid to verify the work of their colleague," said Terrel Harris, communications director for the Executive Office of Public Safety and Security.

Massachusetts Gov. Deval Patrick ordered the lab to be shut down on August 30.