This last episode of Season 3 will cover the sudden death of Arthur John Shawcross, 

• Our last visit was September 8th, 9th, and 10th 2008
• Arthur John Shawcross died November 10th, 2008
• This is the final story

Before he died he says in a letter:

• “You’re Welcome Anthony, I have written and given you what I have never given to anyone else Anthony and that is a blow by blow of the crimes I did in Rochester. As for the other two crimes that will stay hidden. Don't even go there. Actually I have sent you many things that no one has ever gotten from me. You're a good friend Anthony.”
• Art tells Tony that Son of Sam David Berkowitz was in a cult and he didn’t commit the murders alone.This was in 2007 and Tony and Al thought this was prison gossip and mainly bullshit. Now it’s thought to be true. 
• Tony will cover the descriptions of the last 3 victims of Shawcross
• In his last letter Art asks: “Did you get the return photos yet that I signed from your visit?”
• These were photos that he signed from our last visit with Arthur John Shawcross