Artnews_ A painting by Francis Bacon that was stolen in 2015 has been covered in Madrid by Spanish police.

The recovered painting is one of five portraits of the Spanish banker José Capelo that are collectively worth €25 million ($27.1 million). The paintings were stolen nine years ago, in what is believed to be the biggest heist in Spanish history.

Three of the five stolen paintings were recovered in 2017. Since the theft, 16 people, including the person thought to have orchestrated the crime, have been arrested. Authorities are still looking for the remaining missing work.

“Investigations are continuing to locate the remaining work and arrest those in possession of it, with the focus on Spanish nationals with links to organized groups from Eastern Europe,” a statement released by the Spanish police said.

Bacon is one of the most influential painters of the 20th century. His work has achieved incredible sums at auction, with his tryptic Three Studies of Lucian Freud (1969) selling for more than $142 million at Christie’s New York in 2013. At the time, it was the most expensive painting ever sold. More recently, at Sotheby’s New York in May of last year, Bacon’s 1966 painting Portrait of George Dyer Crouching sold for $27.7 million.