"Dr. Palmer was always very smiley," Stober tells PEOPLE. "It was no secret that he often took exotic vacations, but there was never any mention of hunting, not even to us, and we were on very good terms."
But hunt he did, as the world now knows – big-game hunts, leading to the killing last month of Cecil the lion, a beloved research animal that conservation officials say was lured off a Zimbabwe preserve, hit by crossbow and arrow, then tracked, before being shot, skinned and beheaded for a trophy.
After turning the global outrage into an appeal, Oxford University's Wildlife Conservation Research Unit, which had tracked the 13-year-old lion since 2008, said Tuesday that nearly 12,000 donors motivated by Cecil's death have raised almost $600,000 to continue the program's work in Zimbabwe.
Meanwhile, protests and social media vigilantism have kept Palmer, 55, of Eden Prairie, Minnesota, in hiding, along with his wife and two children, since he was named July 28. Vandals this week defaced his Marco Island, Florida, vacation home, reports the Orlando Sentinel.
Paula French / AP
Palmer awaits an uncertain fate: Although a professional hunting guide and a local landowner both face charges in Zimbabwe – which licenses lion hunts but had not issued a 2015 permit to this landowner – no charges have been brought against Palmer, who cannot even be considered for extradition to confront accusations until then, says David Glazier, a professor at Loyola Law School in Los Angeles.
The U.S. Fish and Wildlife Service, which is investigating any possible violations of U.S. law in Palmer's reported $50,000 purchase for the international hunting trip, confirmed that Palmer had reached out to the agency through a representative.
In a note to his patients that echoed his only public statements so far, Palmer expressed "regret" and said: "I had no idea that the lion I took was a known, local favorite, was collared and part of a study until the end of the hunt. I relied on the expertise of my local professional guides to ensure a legal hunt."
The revelation and admission led Palmer's longtime patient to marvel that, while on a trip to Germany, the name of her hometown dentist reverberated though international news reports.
"People all around me are talking about it," Stober told PEOPLE while in Munich. "Everyone is appalled."
So is Stober.
"I'm no vegetarian and have nothing against hunting if a person is going to eat or otherwise make use of the animal," says the cosmetologist from Shorewood, Minnesota. "But to shoot and kill for fun, especially endangered species, I find morally and ethically corrupt.
"I also feel absolutely sick to know that the literally tens of thousands of dollars my family has paid him over the years – my braces, crowns for my parents, bridges for my grandmother, countless cleanings, fillings and tooth whitenings – has gone to fund animal-killing vacations.
"My family has already written a letter," she says, "saying that in good conscience, we cannot continue to support his practice and will be looking for a new dentist."
For more about what's ahead for Cecil's killer, pick up this week's issue of PEOPLE, on newsstands Friday