Brink has filed a lawsuit against Canada's largest airline for nearly $20 million, claiming that someone allowed access to a facility operated by Air Canada at Pearson Airport in Toronto, enabling them to leave with gold bars and cash.

The Miami-based security company is suing Air Canada to recover funds lost during the crisis that occurred last spring.

According to court documents obtained by CBC News, on April 14, Brink was tasked by two Swiss banks - Raiffeisen and Valiant - to transport more than 400 kilograms of gold and $1,945,843 in U.S. banknotes from Zurich to Toronto.

At that time, the value of the gold was approximately $15.1 million.

The shipment was loaded onto flight AC881, which left Zurich at 1:25 PM local time on April 17 and arrived safely at Pearson at 3:56 PM, without any incident.

The cargo shipments – marked with the words BANKNOTES and GOLDBARS – were unloaded from the plane about 20 minutes later and deposited in an Air Canada storage facility on airport grounds about an hour and a half after that, with the lawsuit alleging that this is when things went wrong.

"At approximately 6:32 PM," Brink claims in the documents, "an unknown individual gained access to Air Canada's cargo storage facilities, and there were no security protocols in place to monitor, restrict, or regulate the unknown person's access to the facilities."

The unidentified person handed the air waybill to Air Canada staff - a document that Brink says is linked to an unrelated shipment, and Brink added that the airline accepted the air waybill "without verifying its validity in any way," "upon receiving the forged air waybill, Air Canada employees handed the shipments over to an unidentified individual, who then fled with the shipment."

Police investigations are ongoing, but the gold and cash have not been seen since, and no one has been arrested.

Brink alleges that Air Canada was negligent and "reckless" in failing to follow appropriate security procedures, despite charging higher shipping rates for its "secure service."

According to Air Canada's website, "all valuable shipments are assessed with a fixed handling fee and value" in addition to "assessment fees calculated as a percentage of the declared value for air transportation."

Brink is pursuing the matter in federal court and is seeking a trial in Toronto, while the airline has declined to comment as the case moves through the legal system.