On Saturday morning, I woke up to a text from my brother: “There is an active shooter at the tree of life synagogue in sq hill. Crazy response happening outside.” He lives in Squirrel Hill, near the house where we grew up and not far from the Tree of Life synagogue.

That morning, Robert Bowers, a forty-six-year-old white man from Baldwin, a suburb of Pittsburgh, walked into the synagogue during a bris, a celebration of birth, and opened fire. He carried multiple guns and killed eleven people. As he said after he was taken into police custody, he was motivated by a desire to see all Jews die. It is reportedly the deadliest attack on Jewish people in US history.

“Thirty-eight of your friends have marked themselves safe during The Shooting at Tree of Life Congregation Synagogue, Pittsburgh, Pennsylvania, USA,” Facebook’s dystopian algorithm informed me in a notification. When I clicked through, it also read, ominously, “177 friends not marked safe.”