If he did tumble down the stairs, the glass would have either shattered or at least fallen out of his hand. Usually when someone is falling down a set of stairs, they will drop what they are holding and try to grab hold of something nearby to stop their fall. However, there is nothing on the wall that is out of place or askew. My conclusion is that Queenie arranged Arthur’s body so that it looks like he fell. (evidence #1)
Another reason that I believe that Queenie is lying is that she said, “He was coming down for another drink - he still has the glass in his hand!” If he was coming down for another drink, Arthur would probably have switched the glass to his right hand for balance, since the autopsy confirmed that he is inebriated. In addition, if he was coming down the stairs for another drink, I don’t see how he could have ended up facing up and towards the stairs. If you were heading downstairs and you tripped, you would probably fall and land face down away from the stairs. (evidence