BOSTON (CBS) – Former State Drug Lab Chemist Annie Dookhan changed the results of some of the drug tests she performed, sources told WBZ-TV’s Karen Anderson on Thursday.

In addition, Dookhan admitted to mishandling samples, sources said.

WBZ NewsRadio 1030′s Bernice Corpuz reports

As the investigation into mishandled evidence continues, the fallout grows.

On Thursday, officials announced that one supervisor at the lab, Linda Han, Director of Bureau of Lab Sciences, resigned. A second supervisor, Julie Nassif, Director of the Analytic Chemistry Division was terminated.

Allegations first surfaced last month that Dookhan had mishandled evidence in the lab. Dookhan resigned and the lab was shut down.

As many as 60,000 drug samples may have been compromised, calling into question thousands of drug convictions.

Attorney General Martha Coakley is leading criminal investigation into state drug lab.

WBZ-TV’s Karen Anderson contributed to this report.