The brother of Cecil the lion was reportedly shot dead in Zimbabwe today.
The Zimbabwean Conservation Task Force said it was "absolutely heartbroken" by the news of Jericho's death.
Jericho was the next lion in the hierarchy and was said to be looking after Cecil's cubs after he was killed by US dentist Walter Palmer.
The Zimbabwean Conservation Task Force said on Facebook: "It is with huge disgust and sadness that we have just been informed that Jericho, Cecil's brother has been killed at 4pm today. We are absolutely heartbroken."
A representative for the hunter who allegedly illegally killed Cecil the lion, Dr Walter Palmer, has contacted a US wildlife agency.
The US Fish and Wildlife Service (USFWS), who are assisting Zimbabwe authorities with an investigation over the killing of the 13-year-old lion, said on Twitter that a representative of Dr Palmer had contacted them yesterday.
American philanthropists have pledged to match new donations up to $100,000 to the research team who had been tracking Cecil since 2008.Read the full story ›
Cecil the lion killer Walter Palmer could face up to 10 years in jail if he is convicted in a Zimbabwean court.
The country has called on the US to extradite the 55-year-old dentist after it emerged he had shot the protected animal with a bow and arrow.
Palmer fled the country before the Zimbabwean authorities knew what had happened.
He admits killing black-maned Cecil, who was a tourist attraction, but said he hired professional guides and believed he had the necessary permits.
The life-long hunter has gone into hiding since his identity was revealed by Zimbabwean conservationists.
The man accused of killing Cecil the lion wanted to hunt an elephant after the slaying but "couldn't find one big enough", his guide claims.
Theo Bronkhurst told The Daily Telegraph he never meant to hunt in the land where Cecil was shot and was "devastated" to learn Walter Palmer had killed a protected animal.
He said: "We would never shoot a collared animal. We were both upset. I should have taken the collar to the parks authority but I panicked.
"So we did what had to be done and took the head and skin as the client had paid for the trophy.
"The client asked if we would find him an elephant larger than 63 pounds (the weight of one tusk) but I told him we would not be able to find one so big, so he left the next day."
Mr Bronkhurst claims he "never knew about Cecil, this famous lion" and that four other collared lions had been shot in the same area this year.
Zimbabwe has called for Cecil the lion killer Walter Palmer to be extradited from the US over the "illegal" killing.
Officials allege Palmer, a 55-year-old dentist from Minnesota, broke the law by financing an illegal hunt.
Palmer claims he thought it was organised above board and did not know Cecil was the country's oldest and most famous lion.
Environment minister Oppah Muchinguri said she understood the Prosecutor-General had already started extradition proceedings against the "foreign poacher".
Cecil the lion killer Walter Palmer has been warned "the world will hunt you down" in a message left outside his holiday home.
A sign, with a lion cuddly toy attached, was taped to the front door of the property in California.
It reads: "You are an abomination - the world will hunt you down. Cecil Innocence."
Palmer has not been seen since news of the lion's death broke sparking a furious backlash from animal rights campaigners around the world.
The White House said today it would review a public petition to extradite American dentist Walter Palmer accused of illegally killing Cecil, Zimbabwe's favourite lion.
The petition has exceeded the required 100,000 signatures, and the White House has said it will respond to all petitions that meet that level.
White House spokesperson Josh Earnest said it is up to the Justice Department to respond to an extradition order.
The incident is currently being investigated by Zimbabwean authorities and the US Fish and Wildlife Service, who said that efforts to contact Dr Palmer have been unsuccessful.
An international hunting organisation has suspended the membership of the US dentist accused of illegally killing protected Cecil the lion in Zimbabwe.
Safari Club International, which promotes big-game hunting worldwide, issued a statement saying memberships for Walter Palmer and his guide in Zimbabwe, Theo Bronkhorst, will be suspended while investigations are ongoing.
The Safari Club said "those who intentionally take wildlife illegally should be prosecuted and punished to the maximum extent allowed by law".
The announcement came as the US Fish and Wildlife Service is investigating whether Dr Palmer violated US law against trading in animals that have been illegally killed, transported or sold.
Efforts to contact Dr Palmer, who killed Zimbabwe's favourite lion Cecil in a trophy hunt, have been unsuccessful, a US wildlife agency has said.
The US Fish and Wildlife Service (USFWS) said in a statement yesterday it is deeply concerned about the killing of Cecil and is gathering information to assist Zimbabwean authorities in its investigation into the incident.
On twitter today, it said that efforts to contact American dentist Dr Walter Palmer, who shot the lion with a crossbow, have so far been unsuccessful.
USFWS is investigating the tragic killing of #CecilTheLion. Will go where facts lead. Efforts to contact Dr. Palmer so far unsuccessful.
The USFWS is investigating whether the killing of the beloved lion was part of a conspiracy to violate the Lacey Act, an American law against trading in wildlife that has been illegally killed, a source close the case said.