By Sean Kelly

Boston (WCVB/CNN) - A chemist is accused of mishandling drug evidence at a Boston crime lab.

Authorities say the woman had been involved in testing several thousand drug samples.

State officials confirm the chemist under investigation for allegedly tampering with drug evidence handled an estimated 50,000 samples since 2003. An enormous amount, yet the actual number of people affected is unknown.

"We do not have docket numbers. We don't have police report numbers so it's difficult at this point. We do have counts," said Anne Goldbach, Forensic Services Director for Public Defenders.

Goldbach says the number of people affected is in the hundreds or thousands.

"It's very troubling that people's liberty has been taken away," she said.

She confirmed there are federal cases involved as well, jointly investigated by the state.

Governor Patrick forced the drug lab to shutdown once the extent of the problem became more clear.

One former chemist, Annie Dookhan, is under investigation, but defense attorneys say details of how evidence was handled shows a much wider problem.

"The chemists apparently had custody of these drugs in their own lockers for weeks and months at a time," said Goldbach.

The state's Department of Public Health said it had placed a second lab supervisor on leave pending the outcome of our investigation.

Investigators first learned of a breach in protocol in February over a June 2011 incident in which samples were incorrectly catalogued.

WCVB/CNN