While we wait for JohnM......why not give us your best guess on the conspiracy between Williams, Jarman and Norman? When did they decide to lie?
Williams, Jarman and Norman conspired and decided to lie immediately after the assassination.
They did so because they felt guilty about causing the assassination.
How did they cause the assassination, you ask ?
Here's how...
Williams, Jarman and Norman accidently discovered the 3+ foot cheese sandwich that Saint Patsy had smuggled into the depository. Without any consideration for Saint Oz, each of them ate a foot of the sandwich and left nothing but a few crumbs for Oz.
Naturally, Oz was livid when he discovered his gigantic cheese sandwich had been stolen and devoured.
Oz was so ticked off that he decided to shoot all 3 of the cheese sandwich thieves.
But at the last minute he changed his mind and decided to shoot JFK instead.
The whole BRW story about eating a bone-in chicken sandwich is an obvious fabrication designed to cover up the fact that he was part of the cheese sandwich theft which ultimately resulted in JFK getting his melon blown off.
If they had only known how attached Oz was to his cheese sandwich and how grumpy he got when he was hungry, the entire assassination could have been avoided.
That's why they conspired and lied.