Toronto police are scratching their heads over who left a car dangling from a cable on the Leaside Bridge.

Commuters found themselves doing double takes on Wednesday morning as they drove by the empty shell of a blue sedan hanging from the bridge.

The vehicle prompted a major emergency services response, with police, firefighters, and paramedics all showing up at the scene, close to the Don Valley Parkway. They arrived to find the gutted car with no engine, no passengers inside and the area cordoned off by yellow tape, not put there by police.

Wish I had gotten a pic, but distracted driving is bad.... There's legit a burnt out car dangling from the bottom of the Millwood St bridge over the Don River... —@OntSecGuy

Const. Victor Kwong made the call to 911 during his morning commute.

"I was carpooling into work, and a passenger — actually it was my mother-in-law — was looking into the treed area of the Don River, and she noticed a car dangling there," said Kwong. "It's not a normal sight to see."

'It's the safety factor'

Kwong said he called 911 out of concern for public safety. The area underneath the car includes hiking trails popular with dog walkers, he noted.

"We can't just have people pulling pranks like this, tying objects underneath bridges. It's not just a nuisance factor, it's the safety factor," he said, noting thousands of cars pass under Toronto's bridges everyday.

Around 8 a.m. ET, police believed they'd solved the mystery, tweeting that the car was part of a movie shoot. They walked that theory back a few minutes later, saying there was no shoot authorized or confirmed, leaving Torontonians wondering who would have taken the time to suspend the car, which had no licence plate.

Commuters found themselves doing double takes as they drove by the hanging vehicle. 0:06

"Obviously someone had intentionally put it up there, because it was tied to a winch system," said Capt. Adrian Ratushniak, of Toronto Fire Services, who described the car as a four-door sedan similar to a Honda Civic.

He said crews managed to get the car on the ground just before 10 a.m. — about three hours after the initial call came in. "I haven't seen anything like this in 30 years" with the fire department, Ratushniak said.

Even though the car was successfully grounded, officials are still stumped over who left it hanging from the bridge. A renegade artist? An off-the-grid film shoot? Students up to no good?

"Whatever it is, it did not have proper approval," said Kwong, noting police have now opened up a public mischief investigation and that charges are possible.

Not the first time a city's seen a car-dangling stunt

One theory is that the car was part of a prank like those in years past by university students.

"These are things that come to mind," said Kwong, who suggested it would have taken an engineer to know the strength of the cable and how it would fare holding the weight of the car.

Both the University of Toronto and Ryerson University say they've spoken with their students and have been told they weren't involved.

Engineering student Arin Minasian said he could imagine a few different ways to get the job done, saying it looked like a "low-budget operation."

This sign is posted not far from where the car was dangling from the Leaside Bridge. (Ali Chiasson/CBC)

As the investigation continues, Const. Caroline de Kloet has described what happens next as a "waiting game."

Toronto Mayor John Tory also weighed in on the mystery, when he was asked about it at an unrelated news conference Wednesday morning.

"I just saw some of the pictures myself that came from television this morning, and I was mystified as to how the car ended up there ... I was just shaking my head in disbelief," said Tory.

"It's just a lucky thing that it [was] dangling there, over something where there isn't a developed neighbourhood or a school or a public park."