(INSIDE EDITION) A beloved dog who sniffed out her owner's cancer has passed away from the disease herself.
Heidi the German Shepherd/Lab mix made headlines last year when her owner, Anne Wills, credited the dog's odd behavior with saving her life.
Wills, from Maryland, had owned Heidi, a trained search and rescue dog, for nine years when the pup started acting strangely last February.
"She'd put all of her 125 pound weight up against me and would not move," Anne told INSIDE EDITION. "She was bug-eyed, drooling, panting, panicking, and I'm thinking, 'What in the world is going on with you?'"
But Heidi wouldn't give up.
"She took her nose and buried it into my chest and she'd keep it there," she said. When Anne took the dog's nose away, Heidi would scratch at the area and panic.
This went on for weeks. Anne took Heidi to the vet, but he couldn't figure out what was wrong. Then Anne decided to go to the doctor herself. To her shock, a cat scan revealed that she had Stage 3 lung cancer.
Anne's oncologist, Dr. Enser Cole from Saint Agnes Hospital in Maryland, said Heidi smelled a chemical the cancer was giving off. He credits the canine with saving his patient's life.
"If it had not been for Heidi, Anne would've come to us months, if not years, later, when she developed symptoms and at that point we probably would've had an advanced cancer," Dr. Cole said.
Anne added: "I never in my wildest dreams thought I'd be thanking her for saving my life."
In a sad twist, just two days after INSIDE EDITION met Heidi and Anne, the dog succumbed to cancer herself.
"God bless her for being persistent and letting her mom know, hey, something's wrong," Anne said.
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