The Pacific Beat reported that a total of 42,000 individual items from all over the world — including human remains — were found in the home of a private collector five years ago.
The home belonged to a 91-year-old man called Don Miller, who has since died.
He had been a Christian missionary and had collected some the items from around the world over his lifetime.
"We seized those artefacts that we felt were problematic, that were outright illegal or had been obtained improperly," Special Agent Tim Carpenter from the FBI's special Arts Theft team.