Police are investigating the theft of an estimated $20 million worth of gold and other valuable items after being offloaded from an aircraft at Toronto Pearson International Airport.

According to Inspector Stephen Duivesteyn, a spokesperson for the Peel Regional Police, the “high value” container arrived on a plane Monday evening and was stolen from a holding cargo facility after it was taken off the plane.

“An aircraft arrived here at the airport in the early evening. As per normal procedure, the aircraft was unloaded and cargo was transported from the aircraft to a holding cargo facility,” he told reporters.

Duivesteyn also said that he believes that a crime like this is “very rare.”

“We feel this to be an isolated incident,” he said. “Therefore, for the travelling public that are concerned about coming and flying out, they should have no concern. We do not consider this to be a public safety matter.”

Police would not comment on what airline shipped the cargo, or where the plane arrived from but did say that no arrests had been made or release any information on suspects.

This is not the first time a heist like this has taken place at Pearson airport. According to the Toronto Star, back in 1952, an estimated $215,000 in gold bars was stolen from Malton airport (now Pearson) which would be valued at around $2.5 million today. The theft — which remains unsolved to this day — made headlines around the world.

The Star also reports that in 1952, an armoured Brink’s Van delivered 10 boxes of gold to Malton airport and loaded onto a cargo flight to Montreal and shipped to England. When the plane arrived, there were only four boxes of gold bullion on board. The investigation included the RCMP, OPP and special investigators from Canadian National Railways.