According to Queensland Police, Sarah tried to set Mr Obi and his new lover on fire while his three young children were in the house.
However, the only person the mother-of-four managed to kill was herself.
Mr Obi’s new girlfriend, 30, escaped with burns to her airway along with all three children – aged five, three and two.
Mr Obi’s burning body was dragged from the burning building by a hero neighbour known as Al.
Al stayed with Obi, who suffered burns to 90 per cent of his body, until an ambulance came 35 minutes later.
“He said to me, ‘I’m not going to make it, I’m going to die, I’m going to die, you need to help me. Help me,” the neighbour recalled.
“He was giving me his hand, reaching out to me to hold it, and I wasn’t going to hold his hand because I know about infection control.”
Mr Obi’s current, unnamed girlfriend and the three children have been taken to the Royal Brisbane Hospital.
Weeks before carrying out the attack, Sarah posted a Facebook message that reads: “She’s not toxic bro. You made her like that. Now you think she is crazy. Your decisions reflect her actions. Check yourself.”
Sarah Mudge and Stanley Obi had four children before they broke up.
Sarah Mudge, who ran her own photography business, has multiple photos of Mr Obi and their children on her social media pages.