The UN Secretary-General expressed condolences, demanded an investigation and reiterated calls for the immediate, unconditional release of detained UN personnel | World. Rights chief says Yemeni worker's death was 'utterly devastating' and that his family had received no. Mohammad el Shami had been held by the Houthi militant group since June 6, 2024, UN High Commissioner for Human Rights Volker Tuerk said in a statement.