The 2nd Floor gunman...

[Tom Graves]

[...]

You're you-know-what nuts.

[Royell Storing]

A lower-floor window of the TSBD is a possibility, but I think that a more likely lower firing position was a first-floor or second-floor window of the Dal-Tex Building. Some witnesses believed shots came from that building, and recall that a Mafia man was arrested as he was leaving the building because he appeared to be acting suspiciously. The Dallas police soon released him.

It makes complete sense to assume that one of the gunmen, perhaps two, used a silencer.

   Remember that Elm St slopes downward toward the Triple Underpass. A person standing near the corner of Elm/Houston would have an elevated position in relation to the JFK Limo traveling down Elm St. Bill Newman said shot(s) came from "the garden" which runs down the Elm St Ext across from the TSBD. DPD Officer Smith is seen on the Couch film as he runs down the Elm St Ext. checking those same "bushes". A shooter in this location would be elevated vs the JFK Limo on Elm St.