Army Corps of Engineers, as the federal agency with responsibility for the project, became involved in the question of how to handle the archaeological discovery.

A data recovery plan was developed and formal excavations began around 2001.

What the excavations revealed — the extraordinary scale and antiquity of the cemetery, the biological and cultural richness of the burials — made the question of what to do with the remains both scientifically urgent and legally complicated.

Under the Native American Graves Protection and Repatriation Act, passed by Congress in 1990, federal agencies and institutions receiving federal funding are required to inventory their holdings of Native American human remains and cultural items, notify affiliated tribes, and repatriate those items upon tribal request.

The question of cultural affiliation — which contemporary tribe or tribes are the lineal or cultural descendants of the ancient individuals — is central to the NAGPRA process.