Police will not be laying any charges after a security breach at Toronto's Pearson International airport grounded several flights and forced an Air Canada flight to Brazil to turn around mid-flight.

The red-eye flight from Toronto to Sao Paulo, with 189 passengers on board, was about four hours into its journey when it was ordered to turn back.

Chantal Vallee, head coach of the University of Windsor's women's basketball team, was on the flight and says the captain woke everyone just before 5 a.m. to announce they were turning back.

"He said that for some reason, the government of Brazil would not let us land and that we were an hour and a half away from landing back in Toronto," Vallee told CTV News Channel Thursday morning.

She says while at first everyone assumed it was a joke, they soon began exchanging ideas about what might have prompted the turnaround.

When they landed at Pearson around 6:30 a.m. ET, Vallee noticed several police cars and security on the tarmac.

"And so we realized it must be something or someone on our plane that was being investigated," she said.

Six officers then boarded the plane, searched for someone, and then escorted a young man off. Everyone remained calm, including the man who was escorted away, Vallee said.

Transport Canada confirmed later Thursday that it had recalled the plane, but said that for security reasons, would not disclose the reason.

Air Canada officials explained that the flight was ordered back because a male passenger had boarded the aircraft without proper screening at airport security.

After cameras caught the man entering the boarding area, all departing international flights from Terminal 1 were suspended while Peel Police searched for the passenger in the terminal as well as on flights that had yet to depart.

It turns out that the Air Canada flight to Sao Paulo had taken off just minutes before flights were grounded.

Peel Police later tweeted that a male passenger was identified, located and interviewed. After concluding that no crime had been committed, they said they ended their investigation.

Vallee said she and her fellow passengers were not allowed to leave the arrival area where they got off the plane. She was able to get on a 9:30 a.m. flight to Sao Paulo but before she left, she says she saw the man who was escorted off the plane.

"He was in the waiting area, just wandering on his own, appearing as calm as he was when he was on the plane. It seemed like he was just waiting with us. There was no security around him," she said.