'Sickening' photos show heartless passenger abandoning his dog at Pittsburgh airport where cops found pet tied to a pole in parking garage

An abandoned dog left at Pittsburgh International Airport was found tied to a pole in a parking garage. 

Just hours earlier, the dog was seen being walked through the terminal with a man pushing a luggage cart on CCTV footage.

The suspected owner had the dog - which appeared to be a chihuahua - alongside him on a leash as they made their way through the airport. 

CCTV footage from later on showed the same man with a different type of luggage cart and without the dog - indicating that he had heartlessly ditched the dog. 

Police believe the unidentified man was a ticketed passenger traveling out of the airport. 

While the canine wasn't microchipped, police are continuing to look into the circumstances which would prompt someone to leave their dog behind. 

'There is no excuse for leaving your pets behind,' Allegheny County police said after the heartbreaking discovery.

'Officers responded and were able to untie the dog, which fortunately appears to be in good condition.' 

It's unclear whether the pair had already made it through security or check-in for a flight - but it is understood he left the airport and re-entered. 

The chain of events suggests that perhaps the dog wasn't allowed to fly with its owner - or that it may have cost extra to take the animal onboard the plane.

A similar incident happened in August at the same airport in Pittsburgh.

The woman faced charges for abandoning her dog at a Pittsburgh Airport parking lot after she was told couldn't take the pet on board without a crate. 

Her French bulldog was found 'unattended in a stroller' at around 5:30am near short-term parking at Pittsburgh International Airport.

Officers were able to track down the owner through a microchip in the dog's neck, but said their attempts to contact the unknown woman were unsuccessful.

The seven-year-old canine was found to be in good health after the ordeal and was taken to a local animal shelter, where it is now hoping for a new, kinder home.

While many people on social media said the dog was better off without its owner, the eager flyer could now face charges of animal abandonment from the Pennsylvania state dog warden.

The woman made the shameful decision to leave the dog at the airport after she failed to convince airline staff it was an emotional support animal.