Well, Biogenesis (lab he purchased steroids from) has his name all over their ledgers...he also attempted to buy the lab's information (MLB claims an attempt to impede their investigation)...and he steered other players to Biogenesis.
I'd like to see every stadium where he plays greet him with loud boos!
"...the empty desks of 20 children marked absent today, and forever"
-Poet Richard Blanco at President Obama's Inauguration, 01/21/13