He knew Yusor and Deah's neighbor had threatened them, knocking on their door and flashing a gun as he complained about noise. And he knew that his sister thought the man was harassing them because they were Muslim.

By now, Yousef was beginning to imagine how he and his other sister, Razan, would have to help their parents through the pain if something had happened.

When his father called some hours later, it was even worse than what he had feared. The neighbor, Craig Hicks, had shot and killed his sister and her husband. But also Razan, who had been with them.

Yousef had lost both his sisters and his best friend in an instant.

He got little sleep that night. As morning came, he showered and knelt on his prayer rug. He cried and he prayed.