BOSTON (AP) — A timeline of events surrounding Annie Dookhan, the chemist at the center of a scandal at the Massachusetts state drug lab, based on police interviews with chemists at the Hinton state lab who worked with Dookhan, and with Dookhan herself:

— Sometime in 2007-2008: A lab supervisor first notices Dookhan is testing an unusually high number of drug samples. He notifies her immediate supervisor.