No, they don`t “know” it.. they were chasing a sound that very likely was an echo. Eyewitnesses saw Oswald in the 6th floor window. And oh, by the way.. can anyone explain the “curtain rods” Oswald told Wes Frazier he was carrying into the TSBD?
You have to be very very gullible to not see clearly there was multiple shooters. And I know better than to try and get you out of that brainwashed condidtion.