See photos, video, and story on Kelo. CANTON, S.D. (KELO) — In the spring, nearly 1,000 unmarked graves of indigenous children were discovered on the grounds of former Canadian boarding schools. Following international attention, the U.S. Secretary of the Interior announced an investigation into the history of U.S. boarding schools with a mission to find potential unmarked graves throughout this country and identify the children in them.

Some of those graves are in South Dakota. The state had 25 Indian boarding schools and was also home to the nation’s only insane asylum for Native Americans.

120 Native Americans lived in deplorable conditions until they died at the Hiawatha Indian Insane Asylum. In all, 400 Native inmates were housed here over three decades.

“The threat around the country and we’ve been told by elders that they heard this in boarding school–that if they were bad, they would be sent to Canton and everyone knew it was a death sentence if you were sent there. You didn’t really come out,” Anne Dilenschneider Keeper of the Hiawatha Indian Insane Asylum story, said.

All that remains today of the asylum building is part of the front entrance, which has been incorporated into a sign for the golf course. A few original barns are also still standing. However, several keepers of the Hiawatha Indian Insane Asylum are making sure what took place here is not forgotten.