Steve, I think that your witness statement is a lie, motivated by your need to support Greg.
It can not be corroborated.
There were a number of witnesses in Dallas who smelled gunsmoke, thereby corroborating each other and with no motive for lying.

Seven are named and quoted in the piece I linked to, including a police officer and a senator.

Witness statements are regarded as strong evidence by the courts.
Who are you to demand they be discounted here?

http://listverse.com/2014/06/08/10-reasons-jfks-death-might-have-been-an-accident/