Deborah Madden's first trial in the federal court of U.S. District Judge Susan Ilston in San Francisco ended in a mistrial in October when jurors could not agree on a verdict on the federal charge of obtaining a controlled drug by means of fraud, deception or subterfuge.
Madden, a 29-year civilian employee of the laboratory, admitted in a police interview in 2010 that she took trace amounts of cocaine, but said she took only what was spilled during weighing.
In the federal case, her defense lawyers contend there is no proof of the deception needed for conviction under the U.S. law.
The law is sometimes used to prosecute doctors or pharmacists who fraudulently obtain prescription drugs not needed by their patients.
Madden's actions contributed to the Police Department's closure of the lab's narcotics analysis unit in 2010 and the San Francisco district attorney's dismissal of hundreds of criminal cases that depended on evidence from the lab.
Madden went on leave from her job and entered an alcohol and drug rehabilitation program in December 2009. She retired permanently in March 2010.
U.S. prosecutors stepped into the laboratory case and obtained a grand jury indictment under the federal law in 2011 after the California attorney general's office announced it would not file state charges because of insufficient evidence.