School hauntings

A long time ago, when I was in the fifth grade, several students saw something very strange on the other side of the playground fence: a woman hanged, dangling from one of the trees in the tall grass. I remember seeing her, and others did too. We don't know if it was imagination or reality. I recall that they even sent a psychologist to talk to the students. Mass delusion? Haunting? To this day, my group of friends and I don't know and we dream of finding an answer.