Testimony will start Monday in a misconduct case related to a Massachusetts chemist.
The hearing is focused on why the Hampden County Attorney General's Office gave false information in a case against Sonja Farak.
She is accused of stealing, using, or creating drugs at an Amherst state lab for years.
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In 2013 state prosecutors said the misconduct lasted for just a few months.
Farak's misconduct may have tainted thousands of drug cases.