An animal welfare group is investigating the treatment of a panhandling dog often seen holding a pipe in its mouth for hours outside New York City's professional baseball stadiums.



The American Society for the Prevention of Cruelty to Animals said it sent investigators to Yankee Stadium Sunday to look into allegations by some baseball fans who say the dog named Coffee is being abused by its owner.



But the ASPCA said it was unable to locate the dog or its owner.



"We will continue to monitor the situation and remain prepared to take appropriate action, as warranted," the organization said in a statement.



The dog is often dressed in a Groucho Marx disguise and sits outside Yankee Stadium or Citi Field on game days. She wears a Wright No. 5 jersey for Mets games, pinstripes for Yankee games and has a plastic container for donations at her feet.



Outcry over Coffee's alleged abuse prompted the creation of a Facebook page, "Stop Abusing Coffee," that already has more than 5,000 fans.



According to the page, "Coffee is FORCED to sit outside Citi Field with a pipe in her mouth every Mets home game for hours on end with a shock collar on & no food, water or rest. Something needs to be done about this."



Photos snapped by baseball fans who happen to pass by Coffee do appear to show a shock collar around the animal's neck. In another Facebook photo, it appears the pup has no teeth.



The Mets said it had notified the authorities. The Yankees did not immediately respond to a request for comment.



The fan page was created by Jason Long, who went to a Mets game on Mother's Day this year with his wife Belkis Cardona-Rivera and Cardona-Rivera's mother.



Long and Cardona-Rivera had been to at least 50 Mets games over the last three years, and each time they saw the pup "with no food or water with her owner not too far away," Long told NBC New York.



That Mother's Day game was the final straw, Long explains. The threesome was watching the dog when she decided to lay down.



"In less than two seconds, she prompted herself back up into a sitting position. What could cause a tired dog to do that?" Long said.



"Thousands and thousands of people go to Citi Field and Yankee Stadium unaware of Coffee's suffering," he added. "The mission of the page is to bring animal cruelty awareness to the public and give Coffee a better forever home."

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