Question: Whose assassination did the son of Yusupov Palace participate in?

full_context: Document 1: Rudolf, Crown Prince of Austria: Rudolf, Crown Prince of Austria (Rudolf Franz Karl Joseph; 21 August 1858 – 30 January 1889) was the only son of Emperor Franz Joseph I and heir apparent to the throne of Austria-Hungary from birth. In 1889, he died in a suicide pact with his mistress, Baroness Mary Vetsera, at the Mayerling hunting lodge. The ensuing scandal made international headlines. He was named after the first Habsburg King of Germany, Rudolf I, who assumed the throne in 1273.
Document 2: Leon Czolgosz: Leon Frank Czolgosz (Polish: "Czołgosz" ; May 5, 1873 – October 29, 1901) was an American anarchist and former steel worker who assassinated U.S. President William McKinley in September 1901. Czolgosz was executed just over seven weeks later.
Document 3: Livadia Palace: Livadia Palace (Russian: Ливадийский дворец , Ukrainian: Лівадійський палац ) was a summer retreat of the last Russian tsar, Nicholas II, and his family in Livadiya, Crimea. The Yalta Conference was held there in 1945, when the palace housed the apartments of Franklin Delano Roosevelt and other members of the American delegation - the Russian delegation was housed in the Yusupov Palace, and the British in the Vorontsov Palace some five miles distant. Today the palace houses a museum, but it is sometimes used for international summits.
Document 4: Yusupov Palace (Crimea): The Yusupov Palace (Ukrainian: Юсуповський палац ) is a palace located in the town of Koreiz, near Yalta in Crimea. It was built for Prince Felix Yusupov-Soumorokov-Elston, father of Prince Felix Yusupov (1887–1967) in 1909 by Nikolay Krasnov, the architect responsible for the imperial Livadia Palace in nearby Yalta. The palace, whose style may be described as Renaissance Revival and Roman Revival, boasts a romantic park with exotic plants and a wine cellar founded by Prince Lev Galitzine in the 19th century.
Document 5: Stephen Alley: Captain Stephen Alley was an engineer and MI6 (SIS) agent born in a House of Yusupov Palace, Moscow, Russia. He was educated in both Russia and England and became experienced in building rail transport. He is noted by many authors and documentaries for alleged involvement in the murder of Grigori Rasputin whilst working for the British Military Control Office in Saint Petersburg. Alley was alleged to be the author of a notorious letter to John Scale on 25th December 1916 that, if authentic, is claimed by BBC History to be "the best proof of British involvement in Rasputin's murder"
Document 6: Felix Yusupov: Prince Felix Felixovich Yusupov, Count Sumarokov-Elston (Russian: Князь Фе́ликс Фе́ликсович Юсу́пов, Граф Сумаро́ков-Эльстон ; 23 March [O.S. 11 March] 1887 – 27 September 1967) was a Russian aristocrat, prince and count from the Yusupov family, best known for participating in the assassination of Grigori Rasputin.
Document 7: Mayerling incident: The Mayerling Incident is the series of events leading to the apparent murder–suicide of Rudolf, Crown Prince of Austria (21 August 1858 – 30 January 1889) and his lover, Baroness Mary Vetsera (19 March 1871 – 30 January 1889). Rudolf was the only son of Emperor Franz Joseph I of Austria and Empress Elisabeth, and heir to the throne of the Austro-Hungarian Empire. Rudolf's mistress was the daughter of Baron Albin Vetsera, a diplomat at the Austrian court. The bodies of the 30-year-old Archduke and the 17-year-old baroness were discovered in the Imperial hunting lodge at Mayerling in the Vienna Woods, fifteen miles southwest of the capital, on the morning of 30 January 1889.
Document 8: Gatchina Palace (Fabergé egg): The Gatchina Palace egg is a jewelled, enameled Easter egg made under the supervision of the Russian jeweler Peter Carl Fabergé in 1901, for Nicholas II of Russia. Nicholas II presented it to his mother, the Dowager Empress Maria Feodorovna, at Easter in 1901. The egg opens to reveal a surprise miniature gold replica of the palace at Gatchina (a town south of St. Petersburg) that was built for Count Grigory Orlov and was later acquired by Tsar Paul I. It is one of two imperial Easter eggs in the collection of the Walters Art Museum in Baltimore, Maryland.
Document 9: Gatchina Palace: The Great Gatchina Palace (Russian: Большой Гатчинский дворец ) was built in 1766–1781 in Gatchina town (near St. Petersburg) by Antonio Rinaldi for Count Grigori Grigoryevich Orlov who was a favourite of Catherine II. The Gatchina Palace is located on the hill above Lake Serebryannoe. It combines themes of a medieval castle and a country residence. Palace interiors are exemplary of Russian classicism at the turn of 18th—19th centuries. The Gatchina Palace was one of the favourite residences of the Imperial family.
Document 10: Rasputin the Mad Monk: Rasputin, the Mad Monk is a 1966 Hammer film directed by Don Sharp and starring Christopher Lee as Grigori Rasputin, the Russian peasant-mystic who gained great influence with the Tsars prior to the Russian Revolution. It also features Barbara Shelley, Francis Matthews, Suzan Farmer, Richard Pasco, Dinsdale Landen and Renée Asherson. The story is largely fictionalized, although some of the events leading up to Rasputin's assassination are very loosely based on Prince Yusupov's account of the story. For legal reasons, the character of Yusupov was replaced by Ivan (Matthews). Yusupov was still alive when the film was released, dying on 27 September 1967.
Document 11: Bakhchisaray Palace: The Khan's Palace or Hansaray is located in the town of Bakhchysarai, Crimea. It was built in the 16th century and became home to a succession of Crimean Khans. The walled enclosure contains a mosque, a harem, a cemetery, living quarters and gardens. The palace interior has been decorated to appear lived in and reflects the traditional 16th-century Crimean Tatar style. It is one of the best known Muslim palaces found in Europe, alongside Topkapı Palace, Dolmabahçe Palace, Yıldız Palace, Aynalıkavak Palace, Edirne Palace, Çırağan Palace in Turkey and the Alhambra in Spain.
Document 12: Gavrilo Princip: Gavrilo Princip (Serbian Cyrillic: , ] ; 25 July [O.S. 13 July] 1894 28 April 1918) was a Bosnian Serb member of Young Bosnia, a Yugoslavist organization seeking an end to Austro-Hungarian rule in Bosnia and Herzegovina. He assassinated Archduke Franz Ferdinand of Austria and his wife, Sophie, in Sarajevo on 28 June 1914, setting off a chain of events that would lead to outbreak of the First World War. Princip and his accomplices were arrested and implicated the Serbian nationalist secret society known as the Black Hand, leading Austria-Hungary to issue a démarche to Serbia known as the July Ultimatum. This was used as pretext for Austria-Hungary's invasion of Serbia, which then led to World War I. Princip was a Yugoslav nationalist associated with the movement Mlada Bosna (Young Bosnia) which predominantly consisted of Serbs, but also Bosniaks and Croats. During his trial he stated: "I am a Yugoslav nationalist, aiming for the unification of all Yugoslavs, and I do not care what form of state, but it must be freed from Austria." Princip died on April 28, 1918, from tuberculosis caused by poor prison conditions that had cost him a limb earlier.
Document 13: Baroness Mary Vetsera: Baroness Marie Alexandrine von Vetsera (19 March 1871 – 30 January 1889) was a member of Austrian "second society" (new nobility) and one of Crown Prince Rudolf of Austria's mistresses. Vetsera and Rudolf were found dead, an apparent murder suicide, at his hunting lodge, Mayerling (see Mayerling Incident).
Document 14: Kokkoz Jami Mosque: The Kokkoz Jami Mosque, also known as Yusupov's Mosque, is located in the village of Sokolyne, Crimea. In Crimean Tatar: Kokkoz means “Falcon”. The mosque was built under the patronage of Prince Felix Yusupov in 1910 by a notable contemporary architect Nikolay Krasnov, the author of the imperial residence Livadia Palace.
Document 15: Moika Palace: The Moika Palace or Yusupov Palace (Russian: Дворец Юсуповых на Мойке , literally the Palace of the Yusupovs on the Moika) was once the primary residence in St. Petersburg, Russia of the House of Yusupov. The building was the site of Grigori Rasputin's murder in the early morning of December 17, 1916.
ground_truth: Grigori Rasputin