Attorney General Martha Coakley says a chemist at the Massachusetts State Crime Laboratory in Amherst has been arrested and accused of tampering with drug evidence and possessing drugs.

    Coakley said Sunday that Sonja Farak of Northampton was arrested Saturday night. Officials say it appeared she removed a substance from a case that tested positive for cocaine and replaced it with a counterfeit substance that did not test positive.

    The 35-year-old Farak does not have a listed phone number in Northampton and it wasn't known on Sunday if she is represented by a lawyer.

    Coakley said the Amherst lab contacted State Police on Friday to report a discrepancy in the controlled substance inventory.

    On. Jan. 9, a former chemist accused of faking test results at a Boston drug lab pleaded not guilty to obstruction of justice charges.  (Associated Press)