Mr Addoais is believed to have died after being tortured in Al-Qaseem prison in southern Saudi Arabia earlier this month. His family in Yemen has yet to receive his body.
Alkarama's legal Director, Rachid Mesli confirmed that "Alkarama received information indicating that Mr. Addoais was exposed to severe torture while in Al-Qaseem prison, which eventually led to his death." Mesli maintained however that "the Saudi authorities are seeking a bargaining chip with his family over his burial in either Mecca or Medina."
"On 1 December 2010, the Addoais family was able to quickly see his body for the first time." continued Mesli, "The official cause of death? Pneumonia."
However, the family immediately found the marks of severe torture - the cause of death was clear.
According to his family's testimony, he was arrested on 27 October 2006 by the Saudi General Intelligence services in Al-Naseem, Riyadh.
His arrest was carried out without a warrant and he was arbitrarily detained without charge or trial up to the moment of his death. Throughout his detention he was subjected to various forms of torture and ill-treatment.
During more than four years of detention, Mohamed Addoais was transferred between prisons on several occasions. He was initially detained at Alisha prison, then moved to Al-Hayr prison and finally to Al-Qaseem prison.
There are dozens, if not hundreds of Yemenis detained without legal procedures in Saudi Arabian prisons.
In its appeal to the United Nations' human rights special procedures, Alkarama wrote that "Mr. Addoais' family are convinced that his death was a direct result of the practice of torture and inhumane treatment."
His death as a result of torture is further reaffirmed by the fact that the Saudi authorities not only refuse to do an autopsy to determine the cause of death, but also refuse to send his body back to Yemen.
This is the third case of a Yemeni detainee to die inside a Saudi prison in recent years. Alkarama had already sent the cases of Khaled Ahmed Hatem and Salim Abboud Bahanif to the UN human rights special procedures requesting separate independent investigation into the causes of death.
Khaled Ahmed Hatem was arrested in April 2008 and pronounced dead on 31 August 2008. While Salim Abboud Bahanif died on 29 September 2009 as a result of poor health due to medical neglect, which led to a bout of fatal pneumonia.
Sultan Mohamed Addoais' death is a reminder of the hundreds, if not thousands, of detainees inside Saudi Arabian prisons to be detained under inhumane conditions and suffering from torture.
It is worth noting that Saudi Arabia has been party to the Convention against Torture since 23 September 1997 and has been a member of the Human Rights Council since May 2007.