US Attorney tells judge she withheld exculpatory evidence because it's DOJ policy to protect misbehaving police officers from inappropriate disclosure of embarrassing facts

http://www.roanoke.com/news/local/bedford_county/judge-scolds-prosecutors-takes-up-appeal-by-drug-defendant/article_bcd606ec-d5d2-53cf-bba1-8ed4b6fc0a28.html