When the FBI showed up at Don Miller's home in rural Indiana in 2014 to
"He was very beloved. He was very charismatic," former local reporter Liz Dykes said. Dykes interviewed the 90-year-old former engineer about his time in World War II, his missionary work in Haiti, and most of all, his huge collection of artifacts from around the world.
"The entire house is a museum. There are things everywhere," Dykes recounted. "It was just mind-blowing."
Miller willingly showed his collection to reporters, residents, and even local Boy Scout troops, so when the FBI came calling, she said, "I wanted to know what they were looking for... There had to have been something."
There was: something the FBI hasn't talked about—until now.
"When I first went into his house and saw the size of the collection, it was unlike anything we'd ever seen," Tim Carpenter, who heads the FBI's art crime unit, told CBS News correspondent Anna Werner. "Not only me, but I don't think anybody on the art crime team."
FBI photos – never before shown publicly – give a glimpse of the collection: some 42,000 items, including pre-Colombian pottery, an Italian mosaic, and items from China, some that Miller labeled "Chinese Jewelry" from 500 BC.
"Roughly half of the collection was Native American, and the other half of the collection was from every corner of the globe," Carpenter said.
But the problem? Carpenter said a lot of it had been illegally obtained. Miller admitted he'd gone on digging expeditions in foreign countries and around the United States for decades in violation of antiquities laws.
"Did he understand that he had obtained some things illegally?" Werner asked.
"He did," Carpenter said, adding that Miller admitted to it.
Miller eventually agreed to let the FBI seize some 5,000 artifacts so they could be returned to their countries of origin. But Carpenter said all the FBI's careful planning couldn't prepare them for another, more disturbing discovery.
"About 2,000 human bones," Carpenter said. "To the best of our knowledge right now, those 2,000 bones represent about 500 human beings."
Nearly all of those human remains, he said, were also dug up from ancient Native American burial sites.
"It's very staggering," Carpenter said.
"Why would anybody have that many human bones?" Werner asked.
"I don't know. I truly don't know," Carpenter said.
Native American burial sites dating back thousands of years have been a source of fascination for archeologists for decades. One old government film showed the excavation of an ancient Native American village in Alabama. Over time, many other sites have been looted by people seeking artifacts and even skeletons.
"This comes down to a basic human right," said Holly Cusack-McVeigh, a professor of archaeology brought in by the FBI on the Miller case.
"We have to think about the context of: Who has been the target of grave robbing for centuries? Whose ancestors have been collected for hobby?" Cusack-McVeigh said. "And this comes down to racism. They aren't digging white graves."
Experts determined the remains found at Miller's residence likely came from Native American tribes including the Arikara. In North Dakota, tribal official Pete Coffey is working with the FBI to bring them home.
"All too often here we have been treated as curiosities rather than a people here," Coffey said. "They could very well be my own great, great, great, great grandfather, or grandmother, you know, that had been – I characterize it as being ripped out of the earth, you know."
Miller died in 2015. We wanted to know what his widow thought about all this, so we went to Miller's home, where a Chinese terracotta warrior figure stood guard outside.
"I can't comment on the situation at this time," Miller's wife said.
But Carpenter believes in his later years, Miller understood the ramifications of what he did.
"I think he felt compelled to try and do the right thing and return these home," Carpenter said.
Returning those Native American ancestors home is what Carpenter calls the FBI's most important mission now.
"You have to treat these people with dignity. These are human beings and people. It matters. It has meaning to people today, it has meaning to our children and their children," Carpenter said.
So far, the FBI has already returned items from Miller's collection to several countries, including Cambodia, Canada, Colombia, and Mexico. A Chinese delegation will go to Indianapolis this week to claim artifacts. They have already returned some Native American ancestral remains to tribes in the South Dakota region and are planning a large-scale repatriation of remains to other tribes in the coming months.