In his book "Crime at Mayerling, The Life and Death of Mary Vetsera", Georg Markus claims that what happened at Mayerling was never seriously investigated, and the few investigations that were made were manipulated by the Imperial monarchy. However, on 31 July 2015 the Austrian National Library issued copies of Vetsera's letters of farewell to her mother and other family members. These letters, previously believed lost or destroyed, were found in a safe deposit box in an Austrian bank, where they had been deposited in 1926. The letters, written in Mayerling shortly before the deaths, state clearly and unambiguously that Vetsera was preparing to die alongside Rudolf, out of love for him. They were made available to scholars and exhibited to the public in 2016.