A young Mauritanian blogger whose death penalty for blasphemy was downgraded to a two-year sentence that ended in November is still in detention despite growing calls for his release.Cheikh Ould Mohamed Ould Mkheitir was given a two-year term on November 9 after he repented for charges of insulting the Prophet Muhammad in a blog post, and should have left jail because he had already served four years in jail.He had originally been sentenced to death on December 24, 2014.But on Friday, Rassoul Ould El-Khal, a senior official in the national rights commission, said he was "still in administrative detention awaiting the end of the judicial process."Mauritanian authorities have not commented on his fate since November. An informed source told AFP he was "being held in a secure place in Nouakchott," the Mauritanian capital. "This administrative detention breaches the law," the blogger's lawyer, Fatimata M'Baye, told AFP.Some 20 NGOs on Friday also asked the state to end the "secrecy" and guarantee the safety of the blogger, who is in his thirties.The death sentence has not been applied in Mauritania since 1987.Mkheitir was accused of challenging decisions taken by the Prophet Mohammed and his companions during holy wars in the seventh century.He also attacked the mistreatment of the country's black population, blasting "an iniquitous social order" with an underclass that was "marginalised and discriminated against from birth", and to which he belongs.Modern-day slavery in Mauritania, under a hereditary system of servitude, forces members of the "slave" caste to work without pay as cattle herders and domestic servants, despite an official ban.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.