Musa'id bin Abdulaziz Al Saud was a member of the House of Saud.
Background
He was the twelfth son of King Abdulaziz, the founder of Saudi Arabia. Musa'id was born in 1923. His father, known as Abdulaziz in the Arab world and Ibn Saud in the West, was then the Sultan of Nejd and would become King Abdulaziz of Saudi Arabia in 1932.
His mother was Jawhara bint Saad bin Abdul Muhsin Al Sudairi.
Career
He was the father of Faisal bin Musaid who was the assassin of King Faisal. Before marrying Abdulaziz she had been married to Abdulaziz's full brother, Sa'd bin Abdul Rahman, until Sa'd's death in 1916. Musa'id had two full-brothers Prince Saad, Prince Abdul Muhsin and one full-sister Princess Al Bandari.
He joined a Kuwaiti delegation and lined up to meet the king. The prince took out a revolver from his robe and shot the King twice in the head. His third shot missed and he threw the gun away.
King Faisal fell to the floor. Bodyguards with swords and submachine guns arrested the prince. The king was quickly rushed to a hospital but doctors failed to save him.
Initial reports described Faisal bin Musaid as "mentally deranged." He was moved to a Riyadh prison. He was deemed sane to be tried. He was found guilty of murder.
Hours after the verdict, he was publicly decapitated in Riyadh. The assassin's brother Bandar was also put in prison for one year and later released. Prince Musa'id did not hold any significant administrative positions and hence he was sidelined for the throne.
In addition he seemingly never sought one. He lived an austere private life where he was known to be pious. The Royal Diwan announced that Prince Musa'id had died on 19 August 2013.
He was the second eldest living son of King Abdulaziz at the time of his death next only to Prince Bandar bin Abdulaziz Al Saud. It was announced that funeral prayers for the late prince would be held at Imam Turki bin Abdullah Mosque in Riyadh the next day and a three day mourning period was also declared.