MTG--
You make an excellent post, and yet by your own narrative Deputy Sheriff Luke Mooney was ascending the stairs in the TSBD ~12:50 pm, about 20 minutes after the JFKA.
Mooney says he passed by "two men in plain clothes," somewhere between the 2nd and 6th floor.
There were publisher's offices on TSBD floors 2 through 4 with execs and sales-men. They would typically wear office business attire of the day, which was suit and tie.
I find it hard to fathom that JFKA perps would hang around the TSBD 20 minutes after the JFKA.
Also, are we 100% sure that no Sheriffs or DPD'ers, unrecorded, went to the upper floor of the TSBD about 12:50pm?
While Mooney would have possibly recognized fellow sheriffs, what about a non-fellow DPD'er?
I dunno about this one. In the hub-bub after the JFKA, outright pandemonium, a couple of guys in suits on the TSBD stairs 20 minutes after the JFKA...means there was a conspiracy?
Could have been anybody.
This does not excuse the WC, which essentially conducted a posthumous LN prosecution of LHO...and also suffocated leads to G2 in the process.