Prince Ludwig Rudolph of Hanover (1955-1988) and his wife Isabella of Thurn-Valsassina (1962-1988) both died under mysterious circumstances on 29th of November 1988.
Appearantly Isabella was a drug addict and took an overdose (not sure, if on purpose or not). When LR found her he initially tried to save her, but obviously to no avail. He then called his brother, Ernst August, asking him to take care of his son, Otto (who was by then just about ten months old.)
He was found dead the next day. He had put a pistol in his mouth.
Otto was given in the care of his maternal grandparents and now lives in Salzburg with his grandmother.
I remember reading about their wedding in Royalty magazine. Looking at the photos at the time I thought she looked drugged out of her mind. Turned out it probably was true. Their baby son was only 10 months at the time.