Read this overview of the story. Hossam Armanious was a Coptic Christian and an Egyptian-American who frequented a chatroom at Paltalk, often to argue about Islamic persecution of Coptic Christians in Egypt. According to a family friend, he was threatened in the chat room by some Muslims. They had stated that if he continued to speak out, they would kill him.
Hossam, his wife and his two daughters were found brutally murdered on Friday. Most news outlets are either not carrying the story or are omitting the death threat aspect.