Wired News reports that last week Milanese authorities succeeded in apprehending Leonardo Notarbartolo, the man who is believed to have masterminded the world’s biggest diamond heist to date. Approximately 2.2 pounds of rough, uncut diamonds were found in his possession.

Leonardo Notarbartolo reportedly stole $120 million in diamonds and cash from a bank that was considered so secure that it did not even employ security guards.

Most of the stolen diamonds were never recovered. Notarbartolo was detained for stashing hundreds of diamonds in his BMW a few months after being released from prison for the crime.

Amazingly, Wired News reports that Leonardo Notarbartolo may walk away scot free, with the confiscated diamonds back in his possession.

Notarbartolo claims he purchased the diamonds legitimately for 10,000 euros through an intermediary. The alleged jewel thief reportedly told Wired News that the confiscated diamonds are not precious gemstones, but rather industrial-grade diamonds used to manufacture cutting tools.

“Notarbartolo stated: “These are my diamonds. I got them legitimately.”

Notarbartolo’s defense will likely be based on his claim that he acquired the rough, uncut diamonds legitimately. Rough diamonds are hard to trace. Polished diamonds often feature laser-etched logos or certification numbers that are invisible to the naked eye. It would be very difficult to prove that the rough diamonds in Notarbartolo’s possession are the same diamonds that were stolen from the vault six years ago.

Joshua Davis of Wired News, who originally covered the heist, stated: “I don’t understand the Italian legal system, of course. But speaking on purely logical grounds, if you can’t prove that the diamonds are stolen, then you would logically have to give them back.”