PETA via Reuters, file

People for the Ethical Treatment of Animals says a whistleblower took this photo of a shark in a California pool where a commercial was shot. The shark later died. The American Humane Association, which was on the set, could not confirm if the shark in the photo was the one that died.

The death of a shark that was flown from New York to Los Angeles to film a Kmart commercial is under investigation, but the American Humane Association is denying accusations the creature was mistreated.

The 5-foot white-tipped shark fell ill on March 6 after a film shoot in a 60,000-gallon pool, and oxygen and a shot of adrenaline failed to save its life, the association said in a statement.

"There was absolutely no abuse or neglect involved," said the association, which was on the set to monitor the animal's well-being.

The animal-rights group People for the Ethical Treatment of Animals claimed two whistleblowers on the set  -- one anonymous -- reported the shark's health was jeopardized while it was kept in a "small above-ground pool" in a Van Nuys, Calif., backyard.

PETA, which opposes the use of wild animals in ads, said human actors jumped in and out of the water, causing it stress. Julia Gallucci, an animal behavior specialist for the group, said the tipsters reported filming continued for an hour after the shark started to slow down and roll on its side.

The humane association flatly denied the charges.

"We were there. We did not allow any people in the pool with the shark," said Karen Rosa, senior adviser to the film and television unit.

She said the moment the shark showed signs of distress, it was treated. When it continued to struggle, the shark was sent to an aquatic animal specialist and died later that day.

Rosa said the association has enlisted an independent marine animal expert to investigate the shark's death because "this really troubled us."

In a statement, Kmart said it was "saddened" by the incident.

“We take this matter seriously and safety is always our paramount concern," said Howard Riefs, a spokesman for Sears Holdings, which owns Kmart.

"We have been advised by our agency that the production company responsible for this shoot worked with professional animal handlers and a representative of the American Humane Association for the purpose of monitoring the shark’s welfare."

It's unclear who owned the shark or why and exactly how it was shipped from one coast to the other. Critters of the Cinema -- which procured the shark for the production, according to PETA -- said it signed a confidentiality agreement and could not comment.