ABC News October 27, 2017

'An oath of silence': The secret world of fraternity pledging and how it contributes to hazing deaths

WATCH: Hazing deaths in the US

An intoxicated teen is found unconscious and face down at the bottom of a set of stairs. But no one calls 911 until the next morning, when his breathing is labored and his skin has turned gray. He dies a day later.

Another teen, blindfolded and wearing a 30-pound backpack, loses consciousness in a field. More than an hour goes by before he is taken to a hospital. Multiple traumatic injuries and the delay in treatment are blamed for his death.

A third teen, allegedly forced to drink until he passes out, is left on a couch overnight and later declared dead with an alcohol level of .495, more than six times the legal limit.

These three deaths -- all young college students pledging different fraternities in separate states -- shine a light on the secretive and at times brutal realities of hazing in the pledging process. And for the families left behind, there are often more questions than answers. How could this have happened? Why did no one get help right away? And when did hazing get so out of control?