"The National Academy of Sciences has concluded that a technique the FBI has used for decades to match bullets to crimes is flawed... The study's publication next month could open the door to hundreds, even thousands of appeals, and give defense lawyers in future cases new ammunition for undermining expert testimony... The findings are the latest in a string of controversies and embarrassments this year to hit the FBI lab, which pledged to remake itself after a scandal in the 1990s over bad science."