Charles Darwin letter returned to Smithsonian over 30 years after theft

The 1875 letter, part of correspondence between British scientist and Ferdinand Vandeveer Hayden, was stolen by an employee in mid-1970s, FBI said

More than three decades after a letter by Charles Darwin was stolen, the FBI's art crime team has recovered and returned it to the Smithsonian.

The letter, part of the Darwin's correspondence with an American geologist, Ferdinand Vandeveer Hayden, was written in May 1875 to thank his fellow naturalist for field studies of what became Yellowstone national park.