Animal rights group People for the Ethical Treatment of Animals (Peta) has posted a US$15,000 reward for information leading to the arrest of a shirtless man seen kicking a squirrel off the edge of the Grand Canyon in the US state of Arizona.
Video of the unidentified male luring the squirrel to its widely assumed death went viral this week on YouTube, which has since taken it down.
"It is imperative to find anyone who commits sadistic and violent acts against a vulnerable being," said Peta director Martin Mersereau in announcing the reward. "Animal abusers are bullies and cowards who look to victimise the most vulnerable, defenceless individuals available to them - human or nonhuman - and this man must be caught as soon as possible," he added.
It's not known when the low-quality video was made, but National Parks Service spokeswoman Kirby-Lynn Shedlowski said it appears to have been shot along the Grand Canyon's heavily visited South Rim section.
"It's an ongoing investigation," she said by telephone, adding that the man and a second, similarly bare-chested male seen in the 15-second video "could be long gone".
One of America's greatest natural wonders, the Grand Canyon National Park gets nearly five million visitors a year. Rules strictly forbid the feeding of its varied wildlife.
In the video, the man - wearing dark shorts, a straw hat and no shoes - is seen offering food to the squirrel, with the second man in boxer shorts in the background with a camera. The man lures the unsuspecting rodent to the edge, then slips a running shoe onto his left foot and gives it a swift kick into the air and into the canyon, which is 1.6 kilometres deep.
In the United States, harassing wildlife is a federal offence that can result in six months in prison or a fine of up to US$5,000.
Britain's Daily Mail newspaper quoted Jonathan Hildebrand, who supposedly shot the video, as saying he had no part in the incident and did not know the two individuals. "All I know is that they were French," he was quoted as saying, while Peta said "the perpetrator is rumoured to be French or French Canadian".
Shedlowski could not recall any similar incident in the past.