Three other U.S. citizens, whose names have not been released, were freed in mid-November.Hamen, a former Army master sergeant who worked as a security contractor at facilities in Sanaa where many U.N. staff and other foreigners stayed, was detained, along with a colleague, on arrival at the airport in Sanaa in October. According to a LinkedIn profile under his name, he previously worked as a trainer at U.S. Special Operations Command.