Federal officials say they recovered mathematician and World War II-era codebreaker Alan Turing’s doctoral degree, knighthood medal and other pieces of memorabilia in Colorado in 2018, almost 36 years after they were stolen.

In filings in the U.S. District Court of Colorado Friday, federal officials say they seized the British mathematician’s Princeton University degree, his Order of the British Empire medal and several photos, school reports and letters from his time at Sherborne School, a boarding school in Dorset, England.

According to the seizure notices, a woman named Julia Turing approached the University of Colorado Boulder in January 2018, saying she wanted to loan Alan Turing’s memorabilia to the library. Archivists at the library determined the items were stolen from Sherborne in 1984.

Based on her own admission to investigators and from Sherborne records, Julia Turing visited the school during a larger study of Alan Turing’s life and asked to see his archive, which was stored in a wooden box in a laboratory. School officials said they found a note underneath the box after the theft, reading: “Please forgive me for taking these materials into my possession. They will be well taken care of while under the care of my hands and shall one day all be returned to this spot.”

Julia Turing isn’t related to Alan Turing, but she changed her last name from Schwinghamer in 1988, according to the complaint. A former biology teacher at the Sherborne said Julia Turing claimed she was Alan Turing’s daughter when he gave her a tour of the school.

A month after she reached out to CU Boulder, federal officials searched Julia Turing’s home in Conifer and recovered the items, which are valued at $37,775. The property is in the possession of the U.S. Department of Homeland Security in Denver.

However, the items could have far greater value. One of Turing’s notebooks from 1942 was sold at auction for mor than $1 million in 2015. It was not a part of the items found in Julia Turing’s home.

Alan Turing developed several processes for breaking German military ciphers for British intelligence agencies during World War II and is considered a forefather of computer science and algorithmic design. He died by poisoning in 1954. His life story was most recently portrayed in the 2014 film “The Imitation Game.”

It’s unclear why federal agencies are now saying they recovered these items after nearly two years, or if they are slated for return to Sherborne School.

The U.S. Attorney for Colorado and CU Boulder were not available for comment Monday due to the Martin Luther King Jr. Day holiday.