A small crowd of mourners gathered on Friday for the funeral of the Kazakh opposition activist and YouTuber Aidos Sadykov, who was assassinated in Kyiv, Ukraine — a killing that colleagues said had cast a chill over journalists and exiles in Ukraine and the wider region. A former opposition politician and trade unionist, Mr. Sadykov, 55, lived in Ukraine after fleeing Kazakhstan, his homeland, with his family 10 years ago. He was granted political asylum in Ukraine and, with his wife, ran a...