A South Lake Tahoe man has pleaded guilty to charges of excavation and removal of archaeological resources from public lands after federal agents found tens of thousands of Native American artifacts in his home, according to the U.S. Attorney for the Eastern District of California. Timothy Brian Harrison, 50, was sentenced Tuesday to a year and a day in prison, and was ordered to pay $113,000 in restitution.

He was also charged with one count of misdemeanor count of unlawful possession of methamphetamine.

The arrest followed a years-long investigation in the Sierra Nevada where feds say Harrison dug the artifacts up illegally, CBS Sacramento reports.

Get Breaking News Delivered to Your Inbox

A single snapshot entered into evidence shows what federal agents describe as a treasure trove of Native American artifacts looted from the archeological sites.

Miriam Hinman, one of the federal prosecutors that handled the case, spoke to CBS Sacramento about the case. Hinman also has a master's degree in archeology and chose to be on this case because of her passion for examining artifacts.

A photo provided by the U.S. District Attorney's Office in the Eastern District of California of artifacts seized from Timothy Brian Harrison's South Lake Tahoe home. EDCA News via CBS Sacramento

"The illegal digging, in this case, desecrated ancient sites that were important to the Washoe tribe, and were unusually valuable to archaeologists," Hinman said.

Court documents show Harrison spent more than a decade digging up more than a dozen sites in Alpine and El Dorado County ranging from hundreds to thousands of years old.

The area is the ancestral homeland of the Washoe tribe. Darrel Cruz, t he tribe's director of historic preservation, told CBS Sacramento that "every time they take away an artifact, it takes away a piece of the history, the puzzle that makes up that history."

Federal agents were tipped to the illegal digging by hikers. Court documents show investigators then began following Harrison's movements by installing covert surveillance cameras around the archaeological sites. They also used GPS tracking on Harrison's truck.

Eventually, court documents show they found approximately 302 pounds of artifacts in Harrison's home. None of the artifacts were sold..

"He kept these things for himself, in his house," Hinman noted to CBS Sacramento.

After a decade of digging, destroying centuries of archeological evidence, Harrison has pled guilty and has been sentenced to a year and a day in prison.

The federal government is working with the Washoe tribe on finding the appropriate place to house those artifacts.

The massive investigation was conducted by the U.S. Forest Service, the Bureau of Land Management, the National Park Service, the Drug Enforcement Administration, the Federal Bureau of Investigation, California State Fish & Wildlife Service, California Highway Patrol, and Alpine County Sheriff's Department, according to a press release from the U.S. Attorney's office.