The Supreme Court Prosecutor's Office is investigating the former King of Spain, Juan Carlos de Borbón in connection with the construction of the AVE, that links the cities of Medina and Mecca.
The case will focus on ruling out alleged criminal events which happened after June 2014, when King Juan Carlos I was no longer Head of State.
Juan Ignacio Campos, Prosecutor of the Economic Crimes Chamber, will lead the investigation with the assistance of three other Supreme Court Prosecutors.