Cecil, a protected black-maned lion, was killed outside of a national park in Zimbabwe by an American dentist on hunting trip in 2015.
His death sparked worldwide outrage with many people calling for a ban on game hunting.
Now, three years later, a new book by Lion researcher Dr. Andrew Loveridge has revealed more details surrounding the animal’s final hours.
When researching for his book, Mr Loveridge, who had been studying Cecil for eight years before his death, spoke to game staff, researchers and community members in the Hwange National Park area where Cecil lived.
In the book entitled: "Lion Hearted: The Life and Death of Cecil and the Future of Africa's Iconic Cats," he claims that the lion suffered for a long time after it was shot by an arrow.
A passage from the book which was published in the National Geographic read: “In media reports it was widely touted that Cecil suffered in agony for 40 hours. This claim is inaccurate and exaggerated. It's unlikely he'd have lived that long with such a severe thoracic injury."
But he went on to say: “He most definitely did not die instantly and almost certainly suffered considerably.
“Judging from the events described by Cornelius and the data sent by the GPS collar, the injured lion most likely was killed 10 to 12 hours after being wounded."
According to Mr Loveridge, Cecil’s wound was severe.
“The arrow had missed the vital organs or arteries that would have caused rapid blood loss and a relatively quick death.
“Certainly, the lion was so incapacitated that in all those hours he'd been able to move only 350 meters from the place where he was shot," he said.
Mr Loveridge’s book corroborated accounts that the lion was lured out of the confines of the National Park in order for the hunters to overcome regulations.
Walter Palmer, the man who killed Cecil was publically shamed for the murder, but never faced any charges over the lion’s death.
He has since said that he did not realise Cecil was regarded as a national treasure.
In an interview shortly after the death of Cecil, he said:"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.
"Nobody in our hunting party knew before or after the name of this lion."
Lion Hearted: The Life and Death of Cecil and the Future of Africa's Iconic Cats is out on April 10.