(Ahlul Bayt News Agency) - On 3 June, the deputy interior minister said the prince, who was 77 or 78, was in good health and would return "soon".
Months ago Nayef ordered to arrest and torture anyone who participate in anti-regime protests. Due to this many peaceful Shia protesters have been arrested, tortured and many others killed.
It is noteworthy that approximately 400 visitors including Iranian and Arab Shia Muslims were killed in 1988 by the forces of Nayef's ministry.
He was named crown prince in October 2011 after the death of the previous crown prince, Sultan bin Abdul Aziz.
The succession in Saudi Arabia still passes among the sons of former King Abdul Aziz ibn Saud, who established the modern kingdom during his reign from 1932 to 1953.
Next in line is expected to be Crown Prince Nayef's younger brother, Prince Salman, who is the governor of Riyadh.
Funeral prayers for Saudi Arabia's Crown Prince Nayef bin Abdulaziz al-Saud will be held after sunset on Sunday, the royal court said in a statement on Saturday.