BOSTON (AP) —A chemist at a Massachusetts drug lab who prosecutors say faked test results in criminal cases is expected to plead guilty to charges today.

The judge in the case says she would impose a sentence of no more than five years for Annie Dookhan, who's expected to plead guilty to obstruction of justice, perjury and tampering with evidence.

At least 1,110 criminal cases have been dropped because of tainted evidence.