U.S. Dentist Implicated in Killing Famous Zimbabwe Lion Returns to WorkThe Minnesota dentist whose killing of Zimbabwean lion Cecil sparked global outcry from animal lovers, returned to work Tuesday, in the presence of protestors holding up signs and hurling insults at him. Walter Palmer, who shut his dental practice in Bloomington, Minnesota in July following the firestorm of protests after he was identified as the big game hunter who had killed the rare black-maned lion, did not say a word as he walked into his office. The demonstrators waiting outside Palmer’s dental practice demanded that he be charged and extradited to Zimbabwe to answer for Cecil’s killing. Zimbabwe said in July it had requested Palmer's extradition as a "foreign poacher." No charges have been filed against Palmer, who must be charged in Zimbabwe before he can be extradited. The U.S. Justice Department has said it does no comment on extradition requests. While Palmer has not been charged with any crime, two Zimbabwean men, Theo Bronchorst, a professional hunter, and Honest Trymore Ndlovu, a landowner, have both been charged for killing Cecil, and are currently out on bail. One of the protestors outside Palmer’s practice, Veronique Lamb, who held a “Stop Trophy Killing,” sign, said Palmer should be charged. "He has a big part of responsibility in what happened, and why only the people in Zimbabwe need to be charged? He needs to go back to Zimbabwe and face his responsibilities." “He's despicable. He's a killer," said an emotional Cathy Pierce. “Poor Cecil. I mean how many lions do we have left? Do you have to kill them all? What are our kids, what are our grandkids going to see when they're old?" Palmer, who broke his silence following the deluge of attacks against him, to the Associated Press and Minnesota Tribune, maintained he had done nothing illegal, and claimed not to have known Cecil’s value to the country or the Hwange National Park. Palmer said the public uproar against his actions, have affected his family. “This has been especially hard on my wife and my daughter," Palmer said in the interview published in the newspaper. "They've been threatened in the social media, and again ... I don't understand the level of humanity to come after people not involved at all." In the newspaper interview, Palmer declined to address whether he would return to Zimbabwe to face legal questions. In the interview, Palmer said he wounded the lion with a bow and arrow, tracked it and then delivered a final blow with another arrow over the course of far less than the 40 hours that has been widely reported by media.