To give Rudolph what little credit he deserves he seems to have felt a certain guilt towards his wife (ENTIRELY JUSTIFIED) he wrote her a farewell letter in which he told her to go and be happy in her way. To his credit Franz Joseph was always kind to his son's widow - unlike everybody else - and even supported her desire to remarry which was a HUGE concession to an imperial widow of the time.

Rudolph's several farewell letters and Mary Vetsera's pretty much Prove the murder-suicide btw.