GENOA, Neb. (AP) — Researchers say they have uncovered the names of 102 Native American students who died at a federally operated boarding school in Nebraska.

The Omaha World-Herald reports that the discovery comes as ground-penetrating radar has been used in recent weeks to search for a cemetery once used by the school that operated in Genoa from 1884 to 1934. So far, no graves have been found.

The Genoa school was one of the largest in a system of 25 federally run boarding schools for Native Americans. The dark history of abuses at the schools is now the subject of a nationwide investigation.

Margaret Jacobs, co-director of the Genoa Indian School Digital Reconciliation Project, said some of the names identified so far might be duplicates, but the true death toll is likely much higher.

Jacobs said that many of the children died of diseases including tuberculosis. Some other deaths such as a drowning were reported by newspapers at the time.

When the school closed, documents were either destroyed or scattered across the country. Locating them has proved challenging for both the Genoa project and others working to gather information on the schools.

Many of the names linked to Genoa were found in newspaper archives, including the school’s student newspapers, said Jacobs, who also is a history professor at the University of Nebraska-Lincoln.