An audacious group of robbers made off with a prized 17th-century painting by Flemish painter Pieter Brueghel the Younger from a Church in Northern Italy on Wednesday—or so they thought.

After a tip-off, Italian police covertly switched the Crucifixion for a copy in the church of Santa Maria Maddalena in Castelnuovo Magra, about an hour and a half’s drive from Genoa. The mayor of the small town of around 8,500 residents was in on the secret and a few vigilant members of the congregation, who noticed the picture looked out of place, are reported to have kept silent.

Using a hammer to break the case, the thieves lifted the worthless copy picture and made off in Peugeot car. Police believe two people were involved in the attempted heist.

The town’s mayor, Daniele Montebello, originally stuck to the story that the real painting had been stolen but on Wednesday he revealed that after rumors began circulating that someone could steal the work, the police decided to put it in a safe place, replacing it with a copy and installing some cameras. Montebello told the Guardian: “I thank the police but also some of the churchgoers, who noticed that the painting on display wasn’t the original but kept up the secret.”

Among other artworks housed in the church are sculptures fashioned from Carrara marble, a material made famous by Michelangelo.

The targeted painting, which shows the Crucifixion from above, is similar in composition to another work by Brueghel (1564–1636) that belongs to the Philadelphia Museum of Art. That picture, which is thought to be from around 1617, may be based on a work done by the artist’s father, Pieter Brueghel the Elder (1525–1569).

The younger Brueghel’s auction record stands at $10.7 million, set at Christie’s in 2011 for The Battle Between Carnival and Lent.

According to the Guardian, art crime has fallen in Italy from a reported 906 incidents in 2011 to 449 in 2016. But the country remains a popular destination for thieves because of its rich cultural heritage and plethora of churches filled with art that remain open free and open to the public.

UPDATE: This story has been updated as of March 14 to include new details that emerged about the police replacing the original work with a copy.