Shemar was out in L.A. when a photog asked if he was reacting to Thomas getting fired from "Criminal Minds" ... since they famously had beef on set. Check out the clip ... Shemar says people got it twisted -- denying he was throwing shade at Gibson.
The other prime suspect is Keith Tisdell -- a former friend and co-star who was recently convicted for stealing $60k from Shemar's charity. He definitely did NOT deny it was Tisdell.
As for his current feelings about Gibson? Shemar was polite, for sure, but still seems kinda icy.