Two Zimbabwean men who were arrested for illegally hunting a protected lion have appeared in court to face poaching charges.
Police are still looking for the American dentist Walter James Palmer who allegedly paid 50,000 US dollars (£31,900) to track and shoot the animal with the two men - a professional hunter and a farm owner.
Mr Palmer, from the Minneapolis suburb of Eden Prairie, said in a statement that he was unaware the lion was protected, relying on local guides to ensure a legal hunt.
But the death of Cecil the lion could hit the African economy, a wildlife conservationist has warned.
Jeff Flocken said that the lion, who was shot by an American dentist, pulled in a great deal of tourism.
"He was an animal that was sought out by tourists, who came there, spent money and brought revenue which is so needed in so many of these African countries - to see and take pictures of the animal.
"Now after this one tremendously unnecessary death that revenue can't come in any more."
He added that hunting tours were not rare: "Unfortunately it's very easy to buy a package to kill species in Africa. Typically it's not just a hunt for a lion or a rhino or an elephant but it's a number of species in addition to the one that's the anchor."
Mr Palmer, who has a criminal record related to shooting a black bear, said in a statement: "I had no idea that the lion I took was a known, local favourite, was collared and part of a study until the end of the hunt.
"I relied on the expertise of my local professional guides to ensure a legal hunt."
US court reports show Mr Palmer pleaded guilty to making false statements to the US Fish and Wildlife service about a black bear he killed in Wisconsin. He had a permit to hunt, but shot the bear outside the authorised zone and tried to pretend it was killed elsewhere.
The Zimbabwe Conservation Task Force said Mr Palmer and two other men, a professional hunter and a farm owner, tied a dead animal to a car to lure Cecil the lion out of a national park before shooting him with a crossbow.
Task Force chairman Johnny Rodrigues said the wounded lion was found 40 hours later and was shot dead with a gun.
The lion, which was being studied by researchers at Oxford University, was skinned and beheaded, and attempts were made to destroy its collar which was fitted with a tracking device.
Mr Rodrigues said trackers found the carcass days later.
Professor David Macdonald, who founded the Wildlife Conservation Research Unit at Oxford University, warned that Cecil's killing would lead to a "cascade" of other deaths.
"The death of one lion is not just the death of one lion - it is a cascade. It has consequences," he said. "Cecil was the only male so it is highly likely that the incoming males will kill his offspring."
The two Zimbabwean men could face up to 15 years in prison, the Zimbabwe National Parks and Wildlife Authority and the Safari Operators Association said in a joint statement.
Killing the lion was illegal because the farm owner did not have a hunting permit, it said, although the men maintain they did not know the lion was protected.