A grey wolf that travelled 500 miles from Wyoming to become the first of the protected animals seen at the Grand Canyon in Arizona in 70 years has been shot by a hunter.
The lone female wolf, called Echo, was spotted last autumn near the north rim of the Grand Canyon.
It has now been confirmed that she was killed in Utah by a hunter who said he mistook her for a coyote.
Wildlife advocates have expressed their disbelief, with Bethany Cotton, wildlife programme director for WildEarth Guardians, telling the Guardian: "It's tragic that Echo travelled over 500 miles (800km) only to be cut down by an incredibly irresponsible coyote hunter."
The hunter reported to authorities in December that he had accidentally shot and killed a radio-collared wolf.
It is illegal to kille wolves without a special permit in 48 states, where they are protected under the US Endangered Species Act.
Federal wildlife officials said an investigation is ongoing.
According to the Daily Telegraph, grey wolves have been at the centre of a bitter debate in Western states since dozens were released in Yellowstone National Park and the central Idaho wilderness in the mid-1990s in a bid by wildlife managers to restore animal numbers after they were hunted to near-extinction in the northern Rockies.
Hunters and ranchers blame wolves for preying on livestock and big game animals like elk favoured by sportsmen.
Conservationists argue wolves are restoring public land and mountain forests damaged by overgrazing by deer and elk, whose numbers have swelled through a lack of natural predators.