Who's on first?

Police Officer Marrion Baker was riding his motorcycle toward the rear of the motorcade, and after hearing the shots and seeing pigeons fly off the roof of the TSBD, he parked his motorcycle near the building and rushed inside. Some early news reports and witness statements say a police officer ran into Oswald on the First Floor.

Baker's very first affidavit on November 22 said he went up the rear stairs and when he reached the Third or Fourth Floor, he "saw a man walking away from the stairway." He called to him and the man turned around and came back toward Baker, but Roy Truly said he knew him so they let the man go.

Later, Baker changed his story to encountering a man on the Second Floor, but even that account has a several versions. 

Which one was right?