(IDEX Online) - Police in Canada are investigating the theft of gold and other valuables worth US$15m in what is believed to be the country's biggest ever heist of its kind.A cargo container packed with gold and other "items of monetary value" was stolen from a warehouse near Toronto Pearson International Airport (pictured) that was reportedly unmanned by airport security.Police have revealed remarkably few details in the days following the crime, on 17 April. It wasn't until three days later that they even said the heist had taken place. They haven't said which airline shipped the cargo, where the gold was destined for, or where it had come from. "We're looking at all angles on how this item was stolen, so I don't really have a lot of details on how it was stolen to provide or any suspect," Duty Inspector Stephen Duivesteyn, of Toronto's Peel Regional Police, told reporters.He said the theft took place early Monday evening after cargo from an incoming plane was unloaded and transported to a holding facility."Once this cargo was offloaded at a holding facility, subsequent to its arrival, this high-value container was removed by illegal means," said Duivesteyn. He said it was an isolated and very rare incident.