The Huffington Post reports that Annie Dookhan "was the most productive chemist" at the Hinton State Laboratory Institute in Boston, "routinely testing more than 500 samples a month, while others tested 50 to 150." Here is how Dookhan managed to be so efficient:

She sometimes would take 15 to 25 [drug] samples and instead of testing them all, she would test only five of them, then list them all as positive. She said that sometimes, if a sample tested negative, she would take known cocaine from another sample and add it to the negative sample to make it test positive for cocaine....

One co-worker told state police he never saw Dookhan in front of a microscope. A lab employee saw Dookhan weighing drug samples without doing a balance check on her scale.

In an interview with state police late last month, Dookhan acknowledged faking test results for two to three years. She told police she identified some drug samples as narcotics simply by looking at them instead of testing them, a process known as dry labbing. She also said she forged the initials of colleagues and deliberately turned a negative sample into a positive for narcotics a few times.

Dookhan was arrested last week and charged with obstruction of justice for lying about test results and pretending to have a master's degree in chemistry. The Post says "co-workers began expressing concern about Dookhan's work habits several years ago, but her supervisors allowed her to continue working." According to Massachusetts Attorney General Martha Coakley, "the only motive authorities have found so far is that Dookhan wanted to be seen as a good worker." CBS News reports that "Dookhan tested more than 60,000 drug samples involving 34,000 defendants during her nine years at the lab." 

Radley Balko reveals the secrets of Steven Hayne, another remarkably productive forensic scientist.

[Thanks to Baked Penguin for the tip.]