Colonel Franz Kroeger was an SS colonel assigned by Adolf Hitler to buy the Crystal Skull of Cozan from Renee Belloq. He arrived at the Forteresse Malevil in Marseilles, France in 1933, where he encountered Indiana Jones. Kroeger absconded with the Crystal Skull aboard the U-boat U-357 and escaped from Jones. However en route to Germany, the U-357 struck rocks off the coast of Denmark. Captain Wagner attempted to limp the vessel the rest of the way, but underestimated the amount of damage. The submarine sank, and Kroeger drowned along with Wagner and his crew.