The US dentist who sparked an international outcry after killing a lion in Zimbabwe will not be prosecuted because he had obtained the legal authority to hunt, officials say.
Walter Palmer admitted to killing Cecil the lion in July but has always denied that he acted illegally.
Zimbabwe's Environment Minister Oppah Muchinguri said he could not be charged as all his "papers were in order".
Mrs Muchinguri said Zimbabwe would now review how it issues hunting licences.
The environment minister had previously called for Mr Palmer to be extradited and face prosecution. However, it appears that Mr Palmer broke no laws when he killed the lion using a bow and arrow.
"We approached the police and then the Prosecutor General, and it turned out that [Walter] Palmer came to Zimbabwe because all the papers were in order," Mrs Muchinguru said.
Meanwhile the trial against Mr Palmer's Zimbabwean guide, Theo Bronkhurst, is due to continue on Thursday.
Mr Bronkhurst denies the charge of "failing to prevent an illegal hunt".
After his name was revealed by the press, Mr Palmer's dentistry practice and home were targeted by protesters. He has now returned to work after a two-month break.
The 55-year-old is believed to have paid $50,000 (£32,000) to hunt the lion in Zimbabwe's largest game reserve.
Speaking publicly for the first time about the incident last month, he told the Associated Press and Minneapolis Star Tribune that if he had known who the animal was he would not have killed it.
"If I had known this lion had a name and was important to the country or a study obviously I wouldn't have taken it," Mr Palmer said. "Nobody in our hunting party knew before or after the name of this lion."
Mr Palmer also revealed that his wife and daughter had faced intimidation.
"They've been threatened in the social media, and again… I don't understand that level of humanity to come after people not involved at all," he said.
An avid hunter who had previously visited Zimbabwe four times, Mr Palmer did not rule out returning to the country: "I don't know about the future," he said.
"Zimbabwe has been a wonderful country for me to hunt in, and I have always followed the laws."