A former student shot through the doors of a Christian elementary school and killed three children and three adults after elaborately planning the massacre by drawing out a detailed map and conducting surveillance of the building, police said. The massacre at The Covenant School in Nashville was the latest in a series of mass shootings in a country that has grown increasingly unnerved by bloodshed in schools. MORE: https://www.cbs8.com/article/news/nation-world/shooting-at-nashville-private-school/507-1cd3dec3-09c3-4126-b48a-07e4f2d67034