Investigations on both sides of the border are underway after it was revealed that a package of firearms was shipped from the U.S. to a Bombardier facility in Canada.

On Wednesday, CTV News revealed that two military-grade M4 carbines and two Beretta handguns had been delivered to a Bombardier Aerospace facility in Toronto by FedEx in an unlocked case.

The guns, which are believed to have been sent from Utah, arrived in Canada on Aug. 30. In a statement, Bombardier said the weapons were “delivered in error” and that the company promptly notified police.

A receipt, however, indicated that there were two cases in the shipment, although only one arrived at Bombardier. According to FedEx, the second case, which crossed the border at the same time, has since disappeared.

Authorities in both Canada and the U.S. -- including the Pentagon, Toronto police and the Canada Border Services Agency (CBSA) -- are now trying to determine how the weapons, two of which were stamped “Property of U.S. Govt.,” made it into country.

"We are concerned about those types of weapons coming into this country but we will await the outcome of the Toronto Police Service investigation to determine precisely what happened and the circumstances,” Bill Blair, Minister of Border Security and Organized Crime Reduction, told CTV News on Thursday.

According to Toronto police, the incident is not being investigated as a criminal matter.

Speaking to CTV News, however, security expert Dr. Arne Kislenko questioned how firearms such as these could be sent to Canada and not be investigated as a criminal matter. According to the RCMP, the M4s are “prohibited” firearms while the Berettas are “restricted.”

“The fact that there are really high-powered weapons there suggest at least to me the potential for criminal activity,” Kislenko, a Ryerson University historian, told CTV News.

Firearms arriving in Canada are supposed to undergo an extensive screening process involving both the RCMP and CBSA, yet these weapons somehow managed to slip into the country undetected.

"CBSA is probably most terrified that this would be the negligent side -- that somebody actually did clear them, in which case we have a really big problem,” Kislenko added.

With a report from CTV’s Angie Seth