Italian AI tool spots 2004 stolen Saint Agnes painting, altered to hide it

A 17th-century painting vanishes in 2004

A 17th-century painting of Saint Agnes was stolen from a small church in Sulmona, in the Abruzzo region, on the night of 11 August 2004. For two decades nothing was heard of it. Italy holds a large number of cultural treasures and has long faced art theft. The work had been altered to hide its identity: the lamb the saint held was painted over, her halo was erased and a parchment scroll was placed in her hands. Those changes made the figure look like an ordinary woman, which made the painting harder to recognise and easier to sell.

Spotted at a Parma antiques fair

In October 2024 Carabinieri photographed the paintings on display at the Mercanteinfiera antiques fair in Parma and fed the images into an AI system that compares them with records of stolen works. A few hours later the software flagged a possible match: a painting of a young woman in red and blue holding a scroll. The next day officers returned to the fair with experts, inspected the canvas up close and seized it for further checks. According to the reporting, a manual keyword search would never have worked in this case. Recalling the moment, Salvatore Rapicavoli, a lieutenant colonel with the Carabinieri's cultural heritage command, told the BBC:

“There was something that didn't add up.”

How the Swoads system works

The system is called Swoads, short for Stolen Works of Art Detection System. Instead of matching keywords, it compares subtle colour tones and rough silhouettes, and it can recognise segments of artworks that have been cut up and rearranged. Italy's stolen-art database, maintained since 1969, holds more than one million objects, and officers had previously searched it by typing descriptions one at a time. Some of its images were taken decades ago and are black and white, which made comparison slow. The AI does not replace investigators, who still have to expand the database and make arrests. The system has limits too: it struggles with three-dimensional objects and with telling an original from a copy.

Wider recoveries and return

Since November 2023 the system has helped recover more than 300 large paintings and sculptures, plus some 165,000 smaller objects such as coins, medals, manuscripts and maps. The estimated value of the recovered works is more than 203 million euros. The system now scans auction websites and the internet day and night for stolen art. The Saint Agnes painting was handed back to the diocese of Sulmona on 30 May 2025, more than two decades after it was taken. Articles say that without tools like this, such works could remain hidden for many years.