Only about 15% of all items have been able to claim it, as it is not enough for people to claim, the statement said by the FBI agency Tim Carpenter.
"The biggest recovery in the cultural heritage of the 2014 FBI history" artworks were discovered in 2014, the FBI said in a statement.
A guy led the FBI crime art group to Waldron, Indiana, where thousands of American artifacts and hundreds of American American remains were stored.
Don Miller, the farm owner, "was the scientist who helped build the first atomic bomb" was retired, according to the FBI. He traveled for decades to collect more than 42,000 in his home.
"Don (Miller) would be a good thing to do," said the FBI Agency Tim Carpenter in a statement. "He gathered in every corner of the world."
"But I think it's a passion, it was a Native American cultural asset," he added.
The FBI says some artifacts were illegally obtained.
Before Miller's death in 2015, Miller voluntarily agreed to provide the FBI with "artificial and illegal federal and international treaties" violations.
"He has collaborated with us throughout the investigation," said Carpenter, "and we wanted to take these objects and return to their owners and that the Native American ancestors should necessarily be confused."
For five years, the FBI has worked with archaeologists, anthropologists, tribal experts and foreign governments to manage and return waste. Holly Cusack-McVeigh, an associate professor of anthropology and museum studies at Indiana University-Purdue University Indianapolis, prepares and prepares items for her students.
"Ensure that nothing is thrown into your handbag and we assure you to enter an aircraft's belly." Cusack-McVeigh said everything. "
But it's not easy to determine where everything needs to be returned.
"There is not a single expert to say everything we need to know about this material," said Carpenter.
The authorities wanted to contact hundreds of Native American tribes and identify United Nations members who wanted to identify them on recovered artifacts. They also provide a private website to review and claim items.
However, the future of thousands of elements in an outdoor climate in Indianapolis is still unclear.
"Our main goal is to distribute each of these pieces, at least those that are at least determined to be inadequate or illegally," said Carpenter. "But we need public support and we need the help of the academy, and we need help from our external partners for that."
If the FBI wants to determine whether the Nationwide tribes and nations of the world are requesting international organizations to contact the artifacts agency and send an firstname.lastname@example.org request.
CNN has helped Carma Hassan in this report.