CEDAR RAPIDS, Iowa (AP) – A retired National Park Service official has agreed to serve one year of home detention and to publicly apologize for stealing ancient Native American remains from a museum he managed in Iowa, according to a plea agreement released Wednesday.

Former Effigy Mounds National Monument superintendent Thomas Munson has also agreed to pay $108,000 in restitution for the government's cost of restoring the artifacts and to complete 100 hours of community service.

Munson, 76, is expected to plead guilty to one count of embezzlement of government property on Monday in federal court in Cedar Rapids. He and the U.S. Attorney's Office agree in the plea deal that the “appropriate sentence to be imposed” is one-year of probation with home detention, including confinement on 10 consecutive weekends. U.S. Magistrate Jon Scoles will have the final say on the sentence.

In the plea agreement, Munson admits that he took two boxes of prehistoric human remains in July 1990 from a collection at the monument in northeast Iowa, which was established to protect 200 prehistoric burial and ceremonial mounds constructed between 700 and 2,500 years ago. The bones came from more than 12 different individuals” skeletons and had been excavated from the site decades ago.

Munson, who was superintendent from 1971 until his 1994 retirement, kept the human remains concealed in his home's garage in Prairie du Chien, Wisconsin for more than 20 years. Munson returned one box when the monument opened an inquiry into the missing bones in 2011, and a federal agent found the second box during a 2012 search of Munson's garage. By then, “several of the human bones were broken or fragmented beyond recognition,” the plea agreement states.

The plea agreement doesn't mention Munson's motive. But it notes that the theft came months before the Native American Graves Protection and Repartition Act went into effect, which was designed to require federal agencies and museums to return burial and cultural items to affiliated tribes.

The plea agreement calls for Munson to submit a written “public acknowledgment of guilty and apology” to 12 tribes who trace ancestors to the monument, and to produce an audio and video recording of himself reading that statement.

Prosecutors charged Munson with a misdemeanor instead of a felony because Munson refused to admit the market value of the remains exceeded $1,000, the document says.