Apparently Brian McNamee saved syringes that he used to inject Roger Clemens with steroids from 2000 and 2001. Experts say that steroids could still be detected after 7 to 8 years. McNamee stated that he kept the syringes in case it was ever questioned that Clemens used performance enhancers. If this doesnt sound like a huge attempt of blackmail on McNamee's part then i dont know what is.
http://sports.espn.go.com/mlb/news/story?id=3233878