The state’s embarrassing drug laboratory scandal deepened yesterday with the stunning announcement by Attorney General Martha Coakley and state police Col. Timothy P. Alben that a second chemist has been charged with on-the-clock malfeasance — this time, two weeks after the feds gave her Amherst workshop a clean bill of health.

That lab, like the one accused rogue chemist Annie Dookhan worked at in Jamaica Plain until her arrest in September, is now shuttered, leaving the state’s police and prosecutors only the state police lab in Sudbury to work with.

Sonja Farak, 35 — who acknowledged in an interview with state police in September that she knew Dookhan, had worked on cases with her and “did not notice her doing anything improper” — was arrested at her Northampton home Saturday night on charges she stole cocaine and heroin from evidence she had already certified and replaced the samples with “counterfeit” substances. Farak, a state chemist since 2002, was held on $75,000 bail pending her arraignment tomorrow

Coakley and Alben insisted Dookhan’s and Farak’s cases are “very, very different.” While they hope no criminal cases will be jeopardized, it remains unclear whether or how many cases might be at risk. The Dookhan case has called into question charges and convictions in an estimated 34,000 drug cases and resulted in the freeing of hundreds of inmates.

The state’s district attorneys in a joint statement said last night the Dookhan scandal alone has strained their resources, diverting prosecutors.

“Not only have the governor and Legislature not acted to give the DAs relief with these extraordinary efforts, but prosecutors statewide are now presented with the possibility of unrealistic, unfair and unacceptable mid-year budget cuts,” the DAs’ statement said.

“This scandal might pale in comparison to the Dookhan scandal, but what scandal wouldn’t?” asked attorney Matthew R. Segal, legal director of the American Civil Liberties Union Foundation of Massachusetts.

State Sen. Robert Hedlund (R-Weymouth) said he’s still waiting to see results from legislative hearings already held on the Dookhan case: “We’re not going to beat the drum for another investigation when we haven’t yet seen reaction from legislative leaders responding to investigations that have already happened.”