Police and an investigator with the Stark County Coroner's Office believe that Lady stayed by her owner's side in a field just outside of Hartville for almost a week.
Parley Nichols, 81, was found dead there Wednesday night, about a mile from his home.
Nichols had dementia and was reported missing on April 8.
Even though family members passed out fliers and searched for Nichols, his body was only discovered after Lady barked at a passerby.
"This dog would not leave his side," said Stark County Coroner's Investigator Harry Campbell. "No question, she stayed out there on her own volition.
"(Lady) saw another human and started barking and wailing," said Campbell.
The preliminary findings of an autopsy lead the Stark County Coroner to believe that Nichols suffered a natural death due to heart and lung disease.
Campbell said the dog likely drank water from a nearby drainage ditch. But there were no signs of food near Nichols.
Campbell also said that a local newspaper dated April 7 was found with Nichols.
Family members are now caring for Lady.
Mary Nichols believes that Lady was with her relative the whole time he was missing. When asked if her family takes comfort in knowing that Parley Nichols was not alone when he died, Mary Nichols responded, "Yes."