A French couple is facing years of jail time after stealing almost 90 pounds of sand from Sardinia, the Italian island known for its picturesque beaches. The alleged thieves told police they were taking the sand home because they wanted to keep it as a "souvenir," Italian media reported Monday.

According to the Italian newspaper Corriere della Sera, two French citizens poured white sand into 14 plastic bottles from Chia, a beach in southern Sardinia, and put them in the trunk of their SUV. The couple wanted to take it home as a memory of their vacation, but instead were caught on a ferry en route to Toulon, France.

The pair was charged with theft under aggravated circumstance for having stolen from a public beach. They face between one and six years of jail time, according to the report.

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Sand theft is a growing concern on the island. Tourists bottle the sand up to then auction on online sites, BBC reports.

"Sandy beaches are one of the main attractions of Sardinia," a local environmental scientist told the BBC. "There are two threats: one is due to erosion, which is partly natural and partly induced by the increasing sea level due to climate change; the second is sand stealing by tourists."

A 2017 law made trade in sand, pebbles and shells illegal and punishable with fines of up to $3,300.