FBI and other law-enforcement officials surround the rural home of Don Miller, who has amassed a collection of artifacts that leaves experts "overwhelmed."

A team of law-enforcement officials including FBI agents has swooped down on a rural home in Indiana that houses a bizarre collection of artifacts from around the world.

"I have never seen a collection like this in my life except in some of the largest museums," Larry Zimmerman, professor of anthropology and museum studies at Indiana University-Purdue University Indianapolis, told The Indianapolis Star. Zimmerman added that he is "frankly, overwhelmed."

The collection belongs to Don Miller, an unassuming, 91-year-old Indiana native who is now being called "the real Indiana Jones" for his lifetime of globetrotting adventures. [In Photos: Archaeology Around the World]

Inauspicious beginnings

Born in rural Rush County (roughly 35 miles east of Indianapolis), Miller attended engineering school and joined the U.S. Army Reserve during World War II, at which point his life took a curious turn.

His stint in the Army led Miller to the Manhattan Project, which developed the atomic bomb, where he joined such luminaries as J. Robert Oppenheimer, Enrico Fermi, Albert Einstein and President Harry Truman, the Star reports. Miller was stationed so close to a 1945 atomic bomb test on the Bikini atoll that he suffered partial hearing loss.

For most people, that would be adventure enough, but it was just the beginning of Miller's journeys. After the war, he joined the Naval Avionic Center, where he traveled the globe as a senior consultant and, during his breaks, played the part of amateur archaeologist.

His adventure included some trouble with local authorities. On a trip to the Egypt-Libya border to investigate some ancient ruins, Miller was detained and interrogated under suspicion of being a CIA operative. He reportedly was also arrested during a trip to a Mayan ruin in Mexico.

A lifetime of collecting

Later in life, Miller worked as a Christian missionary in such places as Haiti, and continued to make trips to far-flung locales, including Papua New Guinea, Russia, China and Peru. He also made an 11,000-mile (17,700 kilometers) journey across Australia.

Along the way, Miller amassed a collection of rare artifacts and artworks that has experts gobsmacked.

An ancient Egyptian sarcophagus. A life-size terracotta warrior from China. A rifle used at Army Lt. Col. George A. Custer's infamous "last stand" in 1876. A dugout canoe from South America. A shrunken head. Ming dynasty jade. A chunk of concrete from Adolf Hitler's bunker. An anaconda snakeskin that measures 60 feet (18 meters) long. Aztec figurines. And countless Native American arrowheads.

"The man collects everything, everywhere," friend and fellow church member Amy Mohr told the Star. "He's an amazing piece of history. He's an artifact himself."

Hosting tours and playing the pipe organ

Miller never made any effort to keep his collection a secret, hosting tours for schoolchildren while entertaining them on his massive, ornate pipe organ and regaling reporters with tales of his international escapades.

But all that innocent fun came to an end on Tuesday (April 1), when dozens of armed agents from the FBI and other law-enforcement agencies encircled Miller's isolated house in the farmland of Waldron, Ill.

Police set up roadblocks in the surrounding area, and Miller's house and the outbuildings on his property were abuzz with uniformed officials, black SUVs, squad cars, tents and tractor-trailers.

Ongoing FBI operation

"Over the last several months, an FBI investigation has determined that Mr. Miller may have knowingly and unknowingly collected artifacts, relics and objects of cultural patrimony, in violation of several treaties along with federal and state statutes," FBI special agent Robert A. Jones said at a press conference, according to the Rushville Republican.

"In addition to members of the FBI art-crime team, personnel on-site consist of non-FBI experts in the fields of archaeology, anthropology, object conservation, museum registration, fine arts and antiquity handling, photography, and other experts in Native American studies," Jones added.

Officials have not yet charged Miller with any crime, according to Jones, though the investigation is ongoing and may continue for several more months. "The goal of this operation is to preserve and repatriate these artifacts and relics in accord with international, federal and state law," Jones said.

Follow Marc Lallanilla on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.