Chilling final words of 'Grizzly Man' moments before he and girlfriend were eaten alive by bear

Warning: This article contains content which some readers may find distressing.

An audio recording revealed the final moments of bear enthusiast 'Grizzly Man' and his partner before they were eaten by a brown bear.

Documentary filmmaker Timothy Treadwell - a.k.a. 'Grizzly Man' - spent 13 years visiting Alaska to see and study the animals.

Alas, the 46-year-old and his girlfriend, Amie Huguenard's visit to Katmai National Park in October 2003 would mark their last trip and final experience with a bear.

Audio recording of the attack

Alaska Department of Fish and Game biologist Larry Van Daele explained at the time an 'audio recording' was made 'during the actual bear attack' - Treadwell often recording his interactions with the animals for documentary purposes.

The audio recording reportedly lasted 'for about six minutes' and begins with Treadwell investigating a bear that came into the camp he and Huguenard had set up at around 'twilight' and when it was 'raining very hard at the time', Wolf Song News reports.

However, the sound of rain soon gives way to the sound of the bear attacking Treadwell.

Timothy Treadwell (Lionsgate Films)

Van Daele says you can hear the bear enthusiast 'call for help,' Huguenard immediately unzipping the tent and becoming 'very upset'.

"At her urging, he 'plays dead.' It sounds like the bear then retreated for a couple minutes but returned," Van Daele continues. "It again went after him, and he begged her to hit it with something. She in turn screamed for him to fight. The audio ends with his sounds no longer evident and her screams continuing."

National Park Service rangers later revealed they found 'human remains and clothing' in the stomach of a 28-year-old brown bear they killed.

Authorities confirmed the remains to be that of Treadwell and Huguenard.

Van Daele said: "What caused this individual bear to kill and eat humans is unknown. It was very old but not in remarkably poor condition.''

However, he has a theory.

An audio recording captured the moment the bear attacked the couple (Lionsgate Films)

But why did the bear attack?

Well, despite noting it's 'somewhat risky to speculate' and no one will ever know 'exactly what happened,' Van Daele believes the old bear had 'been hanging around the areas getting the last fish of the season' when he realized there was 'little else available to eat', and so walked along a 'major bear trail' in a bid to put on some 'more fat for the winter'.

When the bear walked by Treadwell's tent, Van Daele proposes he encountered the documentary maker, 'reacted and either bit him and/ or hit him'.

"When he 'played dead,' the bear left, but as is often the case, when Mr. Treadwell started moving again, and/or Ms. Huguenard came to his aid, the bear returned," the expert added. "At this time, for some reason, the bear killed and ate him. I suspect that Ms. Huguenard's screams, which sound eerily like a predator call, may have prompted the bear to return and kill her.

"He then cached her body to be eaten later.''

If you have experienced a bereavement and would like to speak with someone in confidence, contact The Compassionate Friends on (877) 969-0010.