Australian authorities said Thursday they are investigating the illegal killing of at least 65 kangaroos found shot or apparently rammed by a vehicle.

A local wildlife shelter alerted Victorian wildlife officials after finding the eastern grey kangaroos in rural paddocks on June 22 about 75 miles north of Melbourne, officials said.

"At least three of the kangaroos were found alive but were subsequently euthanised due to the severity of their injuries," said the state's Conservation Regulator. "Two kangaroo joeys were recovered and are being cared for at a wildlife shelter."

The marsupials had suffered fatal gunshot wounds and "traumatic injuries consistent with being rammed by a vehicle," the regulator said.

Used shotgun cartridges were found in the area.

Local wildlife rescuer Tania Begg found some of the dead kangaroos on June 22, the Australian Broadcasting Corporation reported.

"It was pretty horrific ... they had broken legs, gunshot wounds, it was shocking," she told the network.

She told the network that she found more dead kangaroos in the days following the initial discovery. 

"It was on roadsides, in paddocks, it was all over the place. It was a massive number of kangaroos," she told ABC. "This is the worst thing I've seen." 

Though kangaroos are protected in Australia, the most common species are not endangered.

This means they can be shot and killed in most jurisdictions, but government permission is needed.

Kangaroos, whose numbers fluctuate between 30 million and 60 million nationally, are frequently culled to keep the population in check.

The animals have a "boom and bust" population cycle -- when fodder is plentiful on the back of a good wet season, their numbers can balloon by tens of millions.

Each year, as many as five million kangaroos are also shot as part of a homegrown industry that harvests their carcasses for meat, pet food and leather.

In:
• Australia