The letter is here.
https://www.aclufl.org/pdfs/2012-06-FloridaNVRANoticeLetter.pdf
Florida's effort to kick people off its voter registration rolls has ensared hundreds of citizens who are legally eligible to vote.
Yesterday, the United States Departement of Justice wrote to Florida similarly expressing concerns about the voter purge. The DOJ letter is here.
http://www.postonpolitics.com/wp-content/uploads/2012/06/0531-DOJPURGELETTER.pdf