"It's long been suspected that ratings agencies like Moody's and Standard & Poor's helped trigger the meltdown. A new trove of embarrassing documents shows how they did it"
http://finance.yahoo.com/news/the-last-mystery-of-the-financial-crisis-154447818.html
http://finance.yahoo.com/news/the-last-mystery-of-the-financial-crisis-154447818.html