More than likely the unidentified rider was only another drifter.
The Euphrates was crossed at Birejil (Til Barsip ?), or Jerablus (Carchemish?), or Tell Ahmar (unidentified), or Thapsacus.
Public knowledge noted the arrest resulted from yet another unidentified tip.
Mention is made of a "Nativity" painted for and sent to the emperor Maximilian, and also apparently of some picture painted for Matthias Corvinus, king of Hungary; both are lost or at least unidentified.
He was apparently shot three times by unidentified assailants firing from a pick-up truck.