DA drops more drug cases due to crime lab scandal

April 2, 2010 4:51:52 PM PDT
San Francisco prosecutors dropped another 20 drug cases Friday in the on-going police crime lab scandal.

About 550 cases have already been dropped because the lab was unable to test drugs.

The police crime lab was closed last month after former employee Deborah Madden was accused of stealing cocaine evidence. Madden has not been charged.

New investigations are now showing the drug lab problems could go back several years and convictions that prosecutors won years ago could be at risk.