Exposure
When he left the counter-intelligence service Redl was succeeded by Major Maximilian Ronge, a man trained by Redl himself. Ronge instigated the practice of checking suspicious mail. One suspect envelope — a poste restante letter to be returned unclaimed — was found to contain a large sum of money as well as references to known espionage cover addresses.
On May 9, 1913, a duplicate letter with money was posted to the same cover name, "Nikon Nizetas". Police detectives were assigned to monitor the post office and follow whoever claimed it. When the letter was finally claimed on May 25, police pursued but lost contact when the suspect, who had picked up the letter and left in a taxi. While the policemen stood wondering what to do, they were handed a stroke of luck beyond imagination: the very same taxi that the suspect had taken returned.
The policemen took the taxi and asked to be driven to the address that the previous customer had been taken to. The taxi drove them to hotel "Klomser" and during the ride there they found a pen-knife sheath in the taxi. Arriving at the hotel "Klomser", they told the management to ask the guests if any of them had lost the sheath and then waited in the lobby. When a guest arrived to claim the sheath, the detectives were shocked to recognise their former boss, Colonel Alfred Redl.
When informed of his exposure, Redl committed suicide by gunshot, which was regretted both by Emperor Franz Josef, who would have preferred that Redl avoid dying in mortal sin, and by Austrian Intelligence, which would have preferred to interrogate him on the exact extent of his betrayal.
Read more about this topic: Alfred Redl