Note! The above scenario does not require the 'investigating' authorities to ever know anything about the existence of an outside crew in charge of the floor-laying project. Rather, it has them needing to go to the most extraordinary lengths to pin the shooting on the patsy whom Mr. Truly, in panicked improvisation, has fed them.
Mr. Truly has to explain his having vouched for a white man caught walking away from the rear stairway several floors up. The information which Mr. Harold Norman gives us allows us to consider a scenario in which the man really did work there (as Mr. Truly said), but in which his presence in the building now needed to be hushed up----------because it would mean having to reveal the presence of the outside crew Mr. Truly had brought in.
Mr. Truly's options are horribly limited here. Unless he can find an alternative 'worker', he has to admit that the assassination team was the external crew which he himself brought in to lay the floor. He needs an alternative 'worker'. But who might fit the bill? Not one of the three black workers who watched the P. Parade from the fifth floor. Not Mr. Jack Dougherty, who does fit the bill location-wise but just doesn't fit the description the motorcycle officer will be giving. Not Mr. Billy Lovelady, who might fit the bill description-wise, but doesn't location-wise (Mr. Truly knows he was out front for the P. Parade).
There is only one option: Mr. Oswald. Mr. Truly, at the time he feeds Mr. Oswald's name to the cops, thinks (erroneously) he is on safe (if deeply unethical) ground, because he saw Mr. Oswald inside the building just after the shooting (small storage room on the first floor). In sacrificing Mr. Oswald, he pushes the 'investigating' authorities into full cover-up and hoax mode. That his patsy turns out to have a commie past only intensifies the monomaniacal focus on him as a suspect. And the Lone Nut story that informs the hoax gets Mr. Truly off the hook: a Lone Nut scenario is the only one that doesn't implicate the man who hired Mr. Oswald. Such would certainly not be the case for an entire team of men brought in on Mr. Truly's initiative.
Again, all of the above supposes
for argument's sake NO foreknowledge by Mr. Truly of the assassination plot. And it obviously has him mention to Mr. Ochus Campbell his sighting of Mr. Oswald in the first-floor storage room BEFORE he has thought to turn the man caught walking away from the rear stairway several floors up into Mr. Oswald.
On this scenario, the 'investigating' authorities know that Mr. Oswald didn't do the shooting, and wasn't the man Officer Baker caught by the rear stairway. Mr. Truly tells them he honestly thought it was Mr. Oswald--------and now has no idea who it can have been. The authorities don't really believe him, but all efforts must now go into pinning the crime on Mr. Oswald. FBI cooks up the lunchroom story, and Mr. Truly comes on board as a compliant witness.
It is said that Mr. Truly spent the rest of his life in great fear of the authorities. He knew that they knew he had lied about the man by the rear stairway. They just didn't know-------and didn't really want to know-------what exactly he was hiding.