A brave eight-year-old boy was beaten to death with a baseball bat after he tried to protect his mother from her apparently abusive boyfriend.

Leland 'Lee' Arnett died four days after he was struck in the head with a bat during a domestic violence incident at his family home in De Soto, Illinois on May 13.

His accused killer Marcus Moultrie, 36, also allegedly attacked his mother Deborah Snider that same night, according to court records obtained by WSIL.

Police were called to the residence around 11pm for reports of a domestic disturbance and found Snider unconscious. Lee had been suffering from a 'serious' head wound.

Both the 31-year-old and little boy were life-flighted to a hospital in nearby St Louis, Missouri, where Lee died on May 17.

'This happened because Lee was trying to protect his mother,' his heartbroken great-aunt Anne Donlan Andrew told The Journal Star.

'That takes a lot to stand up for your mom in a violent situation like that, and he did... I wish he wouldn't have, but he did.' 

Lee was buried last Thursday in Nebraska, where his father and extended family live. His family said he donated his organs as his 'final act of heroism.'

The attack has left Snider fighting for her life, her sister Abigayle revealed in a GoFundMe page created to help the family with funeral expenses and medical bills.

Abigayle said the family intends to 'medically transport' Snider back to Nebraska, but declined to provide further details about her condition due to 'security measures.'

Snider was still recovering in the hospital when she was informed that her son had died, Andrew told the newspaper. She was not able to attend his funeral.

Moultrie has been charged with two counts of first-degree murder and one count of attempted first-degree murder following the attack.

He was initially charged with multiple counts of attempted murder after his arrest on May 14, but prosecutors upgraded the charges after Lee died.

The amended charges include an enhancement alleging the crimes involved 'exceptionally brutal or heinous behavior indicative of wanton cruelty.'

He has pled not guilty to all charges and was ordered to remain in continued detention, court records showed.

Moultrie is due back in court on Tuesday for his final pre-trial hearing, with his trial scheduled to begin on July 6. 

Andrew implied that last month's attack was not the first alleged instance of violence in her niece and Moultrie's relationship.

She claimed that Snider had tried to leave Moultrie once before.

Lee's aunt Laurie Morrison echoed Andrew's claim, telling the newspaper: 'A safe place to go is really what they needed at the time, and it's just tough that they didn't have that.'

She pointed out that the family lived in a 'very small town' which seemingly limited their options for finding a safe haven from the alleged abuser.

Lee is remembered by his loved ones for his big smile, sweet eyes, and the way he 'carried joy with him and shared it freely with everyone around him.'

'He loved with his whole heart and ran full force into every hug, making the people around him feel safe, wanted, and deeply loved,' his obituary stated. 

'More than anything, Lee was a protector. Even at such a young age, he stood up for others and defended anyone who needed kindness or care. 

'His heart was gentle, brave, and compassionate beyond his years.'

The eight-year-old's death was also felt hard by his friends, teachers and classmates.

His elementary school, De Soto Grade School, made and sold keychains of Lee with a frog, his favorite animal. 

The proceeds are being donated to his family.

His classmates also honored his memory by creating a paper chain that featured tributes and messages of remembrance.

If you or someone you know is in crisis, call the National Domestic Violence Hotline at 1-800-799-7233 for 24-hour, confidential support.