The wife of an American man who is accused of travelling with a “mock improvised explosive device” inside a suitcase at Pearson International Airport says the item is not a fake bomb but merely an alarm clock.

Maria Silva says that her husband, Joseph Galaska, was travelling home from Brazil by himself on April 6 after spending time there with her and a friend. She says part of his trip included a layover in Toronto where he was to board a United Airlines flight to Chicago.

Galaska was arrested in Toronto by U.S. Customs and Border Protection after the device was discovered during an inspection of a traveller’s suitcase.

Speaking to ABC’s WISN in Milwaukee, Silva said that she personally saw the item purported by investigators to be a fake bomb and insists that it’s harmless.

“It’s a toy, I swear to God, it's a clock,” she said. "It's not a bomb at all, it's just an alarm clock."

Silva said she returned home from the trip a few days earlier than Galaska.

Then, on April 6, Silva says she showed up at O’Hare International Airport in Chicago to pick Galaska up.

After a few hours passed with no sight of her husband, Silva told WISN she knew something was wrong.

U.S. Customs and Border Protection grounded Chicago-bound United Airlines Flight 547 at Pearson shortly before 7 a.m. for what was initially described as a “major security breach.”

Officials later confirmed that a “mock improvised explosive device” had been found inside a suitcase at the airport’s “Toronto Preclearance Facility.”

Though the device tested negative for explosives, the discovery caused a domino effect of delays for passengers onboard the flight.

While investigating the alleged threat, U.S. Customs and Border Protection revoked all passengers’ “preclearance privileges” to enter the U.S. and ordered them all to clear both Canadian and U.S. customs for a second time.

The flight was held on the tarmac for more than four hours.

One passenger described the whole scenario as “nerve-racking.”

Speaking to ABC, Silva says Galaska tried to explain to authorities that the device was a clock.

She says the clock "looks like a robot."

“They checked and they saw it was nothing” she said. “It wasn’t a bomb, it was a clock.”

Silva insists her husband, a retired tool-and-die maker, is innocent.

“He’s someone who has never done anything wrong to anybody,” she said. “He’s in jail and that’s sad.”

Galaska was charged with one count of mischief in relation to the incident.

He appeared briefly in a Brampton court on Friday but was not granted release. Galaska's son is expected to travel to Brampton over the weekend and post his $5,000 bail, but the Canada Border Services Agency is keeping him in custody "pending further investigation."

It's unclear why Galaska is still being held. The case is currently being heard in a Brampton courtroom.

With files from Sean Leathong.