The Minnesota dentist has gone underground in the onslaught of criticism after he killed a prized African lion named Cecil.
It probably shouldn't come as a surprise; an angry horde of Cecil supporters is calling for his head to be mounted on a wall.
Meanwhile, the U.S. Fish and Wildlife Service is investigating the circumstances surrounding the lion's killing.
"At this point in time, however, multiple efforts to contact Dr. Walter Palmer have been unsuccessful. We ask that Dr. Palmer or his representative contact us immediately," said Edward Grace, the service's deputy chief of law enforcement.
CNN knocked on the door of his Minneapolis home, but no one answered.
His practice, River Bluff Dental, is shuttered, at least for now. A memorial of plush animals piles up at the door.
In a letter dated July 28 to his patients, Palmer said the hunting controversy "has disrupted our business and our ability to see our patients."
"For that disruption, I apologize profoundly for this inconvenience and promise you that we will do our best to resume normal operations as soon as possible," he said in the letter obtained by CNN affiliate WCCO.
Out of his hide
As Palmer went into hiding, it appeared the Internet world was at his doorstep with pitchforks and torches.
The website for the dental practice is no longer available online.
Online reviews are trashing his business.
The hashtag #WalterPalmer
is being used to pepper him with threats and insults.
The Facebook page called "Shame Lion Killer Dr Walter Palmer and River Bluff Denta
l" is some 7,300 members strong.
What's the uproar about?
Palmer is in the public crosshairs after the Zimbabwe Conservation Task Force
said Cecil the lion was lured out of an animal sanctuary in Zimbabwe and shot with a crossbow.
But his death wasn't immediate.
Cecil lived another 40 hours until the hunters tracked him down and shot him with a gun. He was then skinned and beheaded.
The hunters also tried to destroy the GPS collar that Cecil was wearing as part of research backed by Oxford University, the conservation group 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," Palmer said Tuesday in a statement. "I relied on the expertise of my local professional guides to ensure a legal hunt."
Two Zimbabweans have been charged in the case and officials in the African nation say they want to talk to Palmer. The undercover dentist has indicated that he'll cooperate, although he said in a statement that he had yet to be contacted by anyone about the investigation.
The killing garnered international attention.
"I think like most people in the world, we are outraged at what happened to this poor lion," Harald Braun, Germany's ambassador to the United Nations, told reporters Thursday.
Braun spoke minutes after the U.N. General Assembly passed a resolution calling on all countries to crack down on illegal wildlife trafficking and poaching. The vote came after two years of work on the resolution and was not tied to Cecil's death.
Cecil's killing doesn't appear to be the first time Palmer has gotten into trouble while hunting.
A man by the same name and age, and from the same town, illegally killed a black bear in Wisconsin several years ago, according to court documents.
That individual pleaded guilty to making false statements knowingly to the U.S. Fish and Wildlife Service, and was sentenced to one year on probation and ordered to pay a fine of nearly $3,000, records show.
A New York Times article in 2009 that profiled Palmer and his hunting methods said he had served a year of probation over the false statements case.
The Times article detailed Palmer's skill and enthusiasm for using archery rather than firearms to slay animals.
He is "said to be capable of skewering a playing card from 100 yards with his compound bow," it said, recounting his killing of a large elk with an arrow in Northern California.
Outside the office
The mood outside River Bluff Dental was peaceful but ugly Wednesday. Hundreds of protesters gathered there, WCCO reported.
"I just came down here to express my disgust at what he did," Alan Miller told the station.
Sarah Madison brought her son, dressed in a lion costume. "I said we're going to come and we're going to honor Cecil's life."
Above the menagerie of stuffed animals at the door, posters now cover the front facade of the practice.
One sign asked, "Dr. Palmer, why did you kill Cecil?" Another said, "Rot in hell." A third employed the hashtag #catlivesmatter.
The vitriol for Palmer even flowed from the governor's mansion.
"I'm just so disgusted with that man," said Gov. Mark Dayton. "Shoot any lion but lure a lion like that out of the preserve and shoot him, how could anybody think that's sport? Just appalling."
And the mood in the area of Palmer's home, in Eden Prairie, was dicey enough for police to issue a statement saying they were protecting the area -- although Palmer could fend for himself.
"Because of the increased traffic in the neighborhood of Walter Palmer's residence, the Eden Prairie Police Department is monitoring the neighborhood to ensure the safety and security of the residents and their property," the statement read. "The Eden Prairie Police Department is not providing personal protection for Mr. Palmer."
With the storm of criticism continuing to brew, it may be quite some time before the hunter, now hunted, feels like it's safe to come out.