HARARE (Reuters) - Zimbabwe will not charge American dentist Walter Palmer for killing its most prized lion in July because he had obtained legal authority to conduct the hunt, a Cabinet minister said on Monday, angering conservationists.

Walter Palmer arrives at the River Bluff Dental clinic in Bloomington, Minnesota, September 8, 2015. REUTERS/Eric Miller

Palmer, a lifelong big-game hunter from Minnesota, touched off a global controversy when he killed Cecil, a rare black-maned lion, with a bow and arrow outside Hwange National Park in Western Zimbabwe.

Environment Minister Oppah Muchinguri-Kashiri said on Monday that Palmer’s hunting papers were in order, and therefore he could not be charged.

“We approached the police and then the prosecutor general, and it turned out that Palmer came to Zimbabwe because all the papers were in order,” Muchinguri-Kashiri told reporters.

Muchinguri-Kashiri said Palmer would be free to visit Zimbabwe as a tourist in the future but not as a hunter. The implication was that Palmer would not be issued the permits a hunter needs.

The environment minister’s comments immediately drew the ire of the animal conservation group Zimbabwe Conservation Task Force, which maintained that Palmer had committed a crime and said it planned to pursue legal action against him in the United States.

Palmer could not be reached for comment on the environment minister’s statement to reporters.

The 55-year-old dentist had closed his practice in late July after he was publicly identified as the hunter who killed Cecil, drawing widespread criticism on social media and a large demonstration by animal rights advocates at his office in Bloomington, Minnesota, a Minneapolis suburb.

The practice reopened in mid-August without him. Palmer returned to work in early September to a handful of protesters and some public support from patients.

“The fact is the law was broken,” said Johnny Rodrigues, the head of the Zimbabwe task force, which first reported news of Cecil’s killing. “We are going to get our advocates in America to actually see what they can do to bring justice to him.”

The U.S. Fish and Wildlife Service has said it was investigating the killing of the lion.

Two more people still face charges related to Cecil’s killing. Both allegedly were involved in using bait to lure the lion out of his habitat in Hwange National Park so he could be killed.

Theo Bronkhorst, a professional hunter in Zimbabwe, is charged with breaching hunting rules in connection with the hunt in which Cecil was killed. A game park owner is also charged with allowing an illegal hunt. Both have denied the charges.

Bronkhorst is expected to appear on Thursday in a Hwange court where a magistrate will rule on a request by his lawyers that his indictment be quashed.

Parks officials said prosecutors would bring Cecil’s head, which the hunters took as a trophy, to court as an exhibit if the trial goes ahead.

Palmer has previously said that the hunt was legal and no one in the hunting party realized the targeted lion was Cecil, a well-known tourist attraction in the park.

Wildlife hunting, which earned $45 million last year, is an important source of money for Zimbabwe, which is still recovering from a catastrophic recession between 1999-2008.