BLOOMINGTON, MN — (CNN) Dr. Walter Palmer is nowhere to be found.

The Minnesota dentist has gone underground in the onslaught of criticism after he killed a prized African lion with a bow and arrow.

It probably shouldn’t come as a surprise; an angry hoard is calling for his head to be mounted on a wall.

CNN knocked on the door of his Minneapolis home, but no one answered.

His practice, Red River Dental, is shuttered, at least for now. A memorial of stuffed animals piles up at the door.

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 Dental” is some 7,300 members strong.

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.

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.

The mood outside Red River Dental was peaceful, but ugly Wednesday. Hundreds of protesters gathered there, CNN affiliate 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.”

In an email to his patients, Palmer said that under current conditions, it was no longer possible to keep his office open.

“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.

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.” And 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.”

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.

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