SEBASTIAN, FL (WPTV) - A Florida animal activist was booked into jail after he says he tried to save a dog that had been left alone and in intense heat in a supermarket parking lot.

Indian River County S.P.C.A. President Van DeMars took cell phone video of the incident last week.

"This is how dogs end up dying and getting sick," he can be heard saying on the recording. "He's panting," DeMars said of the dog. "This is what happens when they first start to get into heat stress."

Afternoon temperatures were above 90 degrees as DeMars says he stumbled upon the animal in a northern Sebastian Publix supermarket parking lot. The dog was tethered to an SUV and sitting on the asphalt with no owner in sight.

"He was literally choking himself, trying to get under the car," said DeMars speaking a Tuesday, several days after the incident.

DeMars said he waited several minutes, but there was no sign of the dog's human companion. DeMars decided to act. "I made the decision that I'm going to un-click the leash and take him into the shade," he said.

He also called law enforcement. However, the dog owner, 83 year old Robert Huffman of Sebastian, arrived first.

Huffman said that he was not happy that DeMars had untied and moved his 14-year-old male dog named Davey. Huffman said he has done this with his dog numerous times and that the animal was not in danger.

Investigators say Huffman had a water bowl for the dog and that the animal was on a 15 foot leash. Huffman said he was in the Publix store for about 30 minutes.

Read more at WPTV's website.