A former chemist accused of falsifying evidence at a Massachusetts state crime lab where she handled more than 60,000 drug samples was arrested on Friday and charged with obstructing justice and lying about her training.
The scandal shook the very foundation of the Massachusetts criminal justice system - the integrity of evidence used to convict and imprison defendants - and authorities promised to create safeguards to prevent it from happening again.
"Her actions totally turned the system on its head," Coakley said at a news conference.
"People absolutely deserve a system they can trust," Coakley said. "Repairing trust is going to take time."
The governor ordered the lab closed in late August and last week established an office to oversee a review of criminal cases potentially affected by the "failures" there.
Dookhan was charged with two counts of obstruction of justice and a single count of pretending to hold a master's degree in chemistry from the University of Massachusetts. If convicted of the charges, she could face 20 years in prison.
Further charges against Dookhan were expected, Coakley said. She said the criminal activity and misconduct appear to be limited to the single rogue chemist who worked for nine years the Hinton State Laboratory Institute in Jamaica Plain.
The charges brought on Friday stem from Dookhan allegedly lying about the integrity of drug evidence she analyzed on two occasions, the statement said.
Apparently motivated by ambition, Dookhan juggled a case load that was two to three times what her co-workers were able to handle, Coakley said.
"She was very proud of that... we do not have evidence to date of any other kind of motive," Coakley said.
Last month, Dookhan told investigators she "screwed up big time" by intentionally contaminating samples, forging approvals and failing to follow procedures, according to a police report obtained by The Boston Globe. She resigned from the lab in March.
On Monday, officials began examining a first batch of about 1,100 cases of people who are already serving prison sentences based on potentially tainted evidence. A Massachusetts man recently was released from prison after being granted a new narcotics trial as a result of the crime lab investigation.
Dookhan, who was removed from the testing lab in June 2011, said no one else at the lab knew what she had done and that she had disobeyed orders even though she knew it was "wrong." Dookhan said she was simply trying to get more work done.
Asked why she had forged initials to signal approval of her work in a log book, she said, "There was no one available -- no one has the time -- I wanted to get the work done."
State police took over the lab in July and discovered Dookhan's mishandling of evidence was more widespread than previously thought. During her career at the lab, Dookhan handled more than 60,000 drug samples linked to 34,000 cases, the Department of Public Health said.
Department of Public Health Commissioner John Auerbach resigned in the wake of the scandal last week.