BOSTON (AP) — A former Massachusetts chemist accused of faking test results at a state drug lab faces more arraignments in a scandal that could jeopardize thousands of drug convictions.

Annie Dookhan has already been arraigned in three counties on charges accusing her of fabricating test results and tampering with drug evidence while testing substances in criminal cases. She has pleaded not guilty to obstruction of justice and other charges.

She faces two more arraignments Wednesday in Plymouth Superior Court and Bristol Superior Court.

Dookhan was indicted on a total of 27 charges. Authorities shut down the lab in August.

An estimated 200 convicted defendants have been released from jail and had their cases put on hold while their legal challenges are pending.

Copyright 2013 The Associated Press.