A bitter family feud has taken centre stage after Bindi Irwin accused her grandfather of psychologically abusing her.

The embattled family’s long standing issues are a far cry from the heartbreaking letter uncovered in 2016.

It was a note Steve wrote when he was 32, and in it, he detailed his gratitude for his parents and their strength.

“At 32, I am finally starting to figure it out. In good times and in bad, you were there. Your strength and endurance to raise me will not go unrewarded. My love for you is my strength,” the legendary croc hunter penned.

“For the rest of my life I will reflect on the unbelievably GREAT times we’ve shared and will continue to share. You’re my best friends!”

Irwin’s letter would not be found for almost a decade, but four years after writing it, the conservationist would give birth to his daughter Bindi with Robert closely following behind.

Today’s bitter feud is nothing short of devastating, with Bindi insisting her grandfather has never had a kind word to say about her.

The star made the unsettling allegations against Bob in her Father’s Day post (Father’s Day outside of Australia was June 20), which she dedicated to her own father, her husband, Chandler Powell, and her father-in-law.

When Bindi was asked why she left Bob out of the tribute, the new mum did not hold back in her reply.

“Unfortunately my grandfather Bob has shown no interest in spending time with me or my family,” she wrote.

“He has returned gifts I’ve sent him after he opened them, he has ignored my correspondence and from the time I was a little girl he has ignored me, preferring to spend time doing anything else rather than being with me.

“He has never said a single kind word to me personally. It breaks my heart but it is not healthy to engage in an abusive relationship.

“I hope everyone remembers to be kind to one another but most of all care for your own mental health,” she added.

“I have struggled with this relationship my entire life and it brings me enormous pain.”

Close friends and family members of Bob Irwin quickly rebutted the claims, including his biographer Amanda French.

French, who co-wrote Bob’s 2016 autobiography The Last Crocodile Hunter, spoke to Brisbane radio show Stav, Abby and Matt to express her immense grief over Bindi’s comments.

According to Amanda, Bob resigned from Australia Zoo in 2008 and hasn’t seen his grandkids since.

“It’s a surprise with what Bindi came out and said. There were some pretty weighty terms that were thrown around, psychological abuse and all that stuff. You’d have to have some pretty big evidence to back that. It’s a pretty big call to make,” she said.

Another member of the Irwin family, Bethany Wheeler, went on to angrily dispute Bindi’s claims in a Facebook post.

Bethany revealed that she is the “the granddaughter of Bob Irwin via marriage of my father and my Stepmother Mandy as a very young child.”

She went on to call Bob “the most genuinely beautiful human on this planet and has NEVER spoken out or put down anybody! He is a man who sits silently and battles his demons alone, in what is great sadness. He doesn’t retaliate, only prays for his grandchildren’s safety and good lives.”

Wheeler wrote that her “sisters and brothers will happily back me up when I say that Bob Irwin is a passive and beautiful human and these lies need to stop”.

Amanda revealed Bob and Terri Irwin’s relationship suffered after the death of Steve, as the conservationist’s father did not agree with how management quickly began to change.

“He’s maintained a very neutral position about it [resigning] even when he published his autobiography.

“The reason why he did that is because he knew there would be consequences for Australia Zoo. He didn’t see eye-to-eye on issues to do with Australia Zoo at the time and some of the animals.”

In the wake of the international media storm, Bindi announced she would be “taking a break” from social media as a means to protect her mental health.

“I’m taking a break from social media and most of my work in the public eye for a month to be with my beautiful daughter and my wonderful family,” she wrote on Instagram.

“I feel tremendously grateful to share our life and conservation work with you but I need some time to focus on the happiness that is my family (both human and animal).”

Terri Irwin also posted a cryptic yet seemingly pointed message on her own social media.

Taking to Twitter, she shared a post about “avoiding certain people” just days after the family’s feud made headlines.

The full quote was penned by author and military veteran Steve Maraboli, and reads: “Avoiding certain people to protect your mental health is not a weakness … It’s wisdom.”

She captioned the snap, “Thank you @SteveMaraboli. Another jewel. Caring for others seems to be easier than caring for ourselves.

“It takes courage to follow through on what we know is the right thing to do. Wishing everyone the best to be brave and wise. It’s worth it!”