June 7 (UPI) -- U.S. agencies returned a stolen letter written by Christopher Columbus in 1493 to Spain on Wednesday.
The U.S. Immigration and Customs Enforcement and Department of Justice returned the letter, detailing Columbus' findings in America, after it was stolen from the National Library of Catalonia in Barcelona and later sold for about $1 million.
"I am pleased to be able to return a priceless piece of cultural property to its rightful owner," said Alysa D. Erichs, acting deputy executive associate director of Homeland Security Investigations.
HSI conducted a seven-year joint investigation with the U.S. Attorney's Office in Delaware after receiving a tip that multiple 15th century manually printed copies of the Columbus letter were stolen from European libraries and replaced with forgeries.
An investigation determined the National Library of Catalonia's copy of the letter was stolen and sold in November of 2005 for 600,000 euros by two Italian book dealers.
In March 2013, investigators learned it had been sold again in June 2011 and the U.S. Attorney's Office for the District of Delaware negotiated with the individual in possession of the letter to volunteer to transfer it to HSI special agents.
Experts examined the letter in March 2014 and determined "beyond all doubt" it was the same copy that had been stolen from the National Library of Catalonia.
"The cooperation between Homeland Security Investigations and special units of the Guardia Civil has born great fruit in ensuring the return of stolen cultural property to Spain," Ambassador of Spain to the United States Pedro Morenés said.
This was the second stolen Columbus letter ICE has been able to return, with the first being returned in May 2016.