On 23 June 2014, he was abducted by Ethiopian security forces while in transit in Yemen's Sana'a International Airport and held at an unknown location in Ethiopia.
During the Derg's Red Terror campaign of 1974, his younger brother Ameha Tsege was murdered by the security forces and Andargachew fled Ethiopia.
[11] In the UK he studied Philosophy at University of Greenwich in the early 1980s and wrote his dissertation on the German philosopher Immanuel Kant.
When Derg was overthrown in 1991, Tsege went back to Ethiopia to help the newly formed Ethiopian People's Revolutionary Democratic Front (EPRDF) government led by his former university friend Meles Zenawi.
[13] After his release, he returned to London, where he was able to campaign against the regime by testifying at different government or international organisations including the US congress and European Commission of Human Rights as well as think tanks such as Chatham House.
He was arrested by Yemeni security forces, in collaboration with Ethiopian intelligence service members, at Yemen's Sana'a International Airport while in transit from the United Arab Emirates to Eritrea.
[15][16][20][21] In February 2015, an early day motion was tabled within the UK parliament, recognising Tsige's 60th birthday, and calling for pressure to be applied to the Ethiopian government, in order to secure his release.
[23] In October 2017, it was reported that both the president of the Law Society and the chair of the Bar Council had urged the UK's Foreign Secretary to work to secure Tsege's release.
Later in November 2020 he published his third book "Yetafaghu mastawesha" which is a story that narrators his abduction from Yemen airport to his experience as prominent political prisoner for four years in unknown location in Addis Ababa.
[citation needed] In late November 2021, Andargachew made statements that researcher Mehari Taddele Maru interpreted as incitement to genocide.