Annie Dookhan sits in Suffolk Superior Court moments before her arraignment in Boston, Thursday, Dec. 20, 2012. Dookhan, the former chemist at the center of a U.S. drug testing scandal, pleaded not guilty to charges including perjury and tampering with evidence. (AP Photo/Steven Senne, Pool)

Associated Press
Annie Dookhan sits in Suffolk Superior Court moments before her arraignment in Boston, Thursday, Dec. 20, 2012. Dookhan, the former chemist at the center of a U.S. drug testing scandal, pleaded not guilty to charges including perjury and tampering with evidence. (AP Photo/Steven Senne, Pool)
Annie Dookhan sits in Suffolk Superior Court moments before her arraignment in Boston, Thursday, Dec. 20, 2012. Dookhan, the former chemist at the center of a U.S. drug testing scandal, pleaded not guilty to charges including perjury and tampering with evidence. (AP Photo/Steven Senne, Pool)