Second Mass. crime lab chemist accused of evidence tampering

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.