International rights group urged Houthis in the Yemeni capital Sanaa to release a prominent activist “immediately and unconditionally.” 
Hisham Al-Omeisy, 38, was detained on Aug. 14, 2017. Human Rights Watch (HRW) said Al-Omeisy has been an important public voice in  Yemen, providing commentary on the country’s conflict.
Al-Omeisy used social media to report and analyze events in Yemen, where he tweeted in English and Arabic.
“Yemen, more than ever, needs activists like Hisham Al-Omeisy to bring attention to the devastation that war, famine, and disease have wrought on the country and its people,” said Sarah Leah Whitson, Middle East director at Human Rights Watch. “Houthi authorities should immediately release Al-Omeisy and return him safely to his family.”
According to HRW, approximately 15 security officers arrested Al-Omeisy in the Jawlat Al-Misbahi neighborhood where he was held in an undisclosed location without charges and denied access to family and lawyers.
Sanaa and much of Yemen have been under Houthi control since September 2014. The formation of a governing council to run the country was announced by the Houthis and ousted President Ali Abdullah Saleh’s General People’s Congress on July 28, 2016. The Supreme Political Council oversees the Sanaa-based Interior Ministry, which in turn supervises detention sites in Houthi and Saleh-controlled Yemen.
In Houthi and Saleh-held areas, many journalists and activists have been arbitrarily detained and beaten and groups’ offices closed or looted.
“All authorities in Yemen should immediately cease targeting, harassing, and arbitrarily detaining activists and journalists,” HRW said.
The New York-based group has documented 66 cases of abuse against Houthi-Saleh forces in which they arbitrarily detained people or where individuals were forcibly disappeared, including two deaths in custody and 11 cases of alleged torture or other ill-treatment, in addition to child abuse.
HRW demanded responsible authorities from all sides across Yemen to immediately free those wrongfully held, end detention without access to lawyers or family, and prosecute officials responsible for mistreatment.
According to international human rights law, an enforced disappearance occurs when the authorities take someone into custody and deny holding them or fail to disclose their fate or whereabouts. “Disappeared” people are at greater risk of torture and other ill-treatment, especially when they are detained outside formal detention facilities, such as police jails and prisons.
International human rights and humanitarian law protects the right not to be arbitrarily detained, tortured or ill-treated, or forcibly disappeared.
Those detained have the right to be informed of the specific grounds for their arrest, be able to fairly contest their detention before an independent and impartial judge, have access to a lawyer and family members, and have their case periodically reviewed.
HRW director, Whitson, warned Houthis of “future prosecution,” in case they failed to comply with the group’s demands. “Members of Yemen’s warring parties are putting themselves at risk of future prosecution if they don’t account for the whereabouts or otherwise mistreat those they have detained,” Whitson said

source:Arab News