Marcus was killed in 1943 over a disputed artifact at the American
Museum. Did it have anything to do with Mac, a rival archaeologist
of Indy? And/or was the artifact a Crystal Skull?
Marcus "aquires artifacts"
for museums by paying people like Indiana Jones to globe-trot across
the planet for fame and fortune.
Marcus was friendly with Henry
Jones, Indiana's father, and with Abner Ravenwood, father of Marion.