NORTHAMPTON, Mass. -- A chemist at a state crime lab tampered with drug evidence, authorities said Sunday in Massachusetts, where another chemist at a different lab was accused last year of faking test results in a scandal that threw thousands of criminal cases into question.Sonja Farak, of Northampton, who works at a lab in Amherst, in western Massachusetts, removed a substance from a case file that tested positive for cocaine and replaced it with one that did not test positive, state Attorney General Martha Coakley said.Farak, 35, was arrested Saturday. She is also charged with possession of heroin and cocaine.The lab contacted state police Friday to report a discrepancy in inventory, Coakley said at a Boston news conference.She said that officials do not believe Farak's alleged tampering will undermine evidence."On its face, the allegations against this chemist do not implicate the reliability of testing done or fairness to defendants," she said.
Last month, the other chemist, Annie Dookhan, was indicted on 27 charges in a case that threatens to unravel thousands of drug convictions. Dookhan, also 35, of Franklin, resigned in March during an internal investigation by the state Department of Public Health. State police closed the Boston lab where she worked in August after taking over its operation and discovering the extent of Dookhan's alleged misconduct.Unlike the allegations against Dookhan, the accusations against Farak do not involve falsification of tests or dry labbing, which is visually identifying samples instead of performing a required chemical test, the attorney general said.Dookhan has pleaded not guilty to various charges.Farak does not have a listed phone number and it's not clear whether she has a lawyer.The Amherst lab has been closed temporarily and chemists will be transferred to Sudbury, Col. Timothy Alben, head of the state police, said at the news conference.Farak is due to be arraigned Tuesday in Eastern Hampshire District Court in Belchertown.