Mahlangu, of Mamelodi, told Judge Bert Bam that she loved Nelly Masangu, and only wanted to teach the child a lesson by pouring paraffin over her and setting her alight.
She claimed the teenager had stolen money from her and she simply wanted to scare her.
Mahlangu thought she had all in hand and would douse the flames before they engulfed the girl. Nelly, however, died a few days later in hospital of third-degree burn wounds.
Mahlangu pleaded not guilty to murder as she said she did not have the intention to kill her.
She took care of the teenager since she was 5 after her mother - Mahlangu’s youngest sister - died. Mahlangu also took care of one of her other siblings’ daughters, only identified as Nomsa, after her mother had died.
Nomsa, with the financial aid of Mahlangu, is studying towards a degree at Unisa.
Mahlangu told the court that she had the same high hopes for Nelly and she had set up a university fund for her. “The money is still in the bank as it was when she died,” an emotional Mahlangu said.
She explained that she suspected that Nelly had stolen R500 that had been left in the house. She had confronted the teenager about it, who denied taking the money.
On October 1, 2015, she took Nelly to the police station, in the hope that she would confess to taking the money. The teenager persisted that she was not the thief and the police referred the pair to a social worker.
Mahlangu said she left the teenager with the social worker in her office in the hope that she would confess to taking the money.
They eventually left the office of the social worker with Masangu still denying that she had taken the money. The social worker instructed them to return on October 5 for another session, but this never happened due to the incident.
On October 4, Nomsa was home for the school holidays and the three of them were at Mahlangu’s home. There were also some tenants present who lived on the property.
Mahlangu said because this was not the first time that the teenager had taken money from her, she decided to scare her.
“I decided to pour paraffin over her and to pretend that I was going to burn her. I believed that she would never burn because I was going to put the fire out myself.”
Mahlangu said when the teenager caught fire, she tried to douse the flames by removing her clothes. “Unfortunately she slipped out of my hands and ran away.
“As she ran further away the flames became even more. I and other tenants poured water at her in an effort to put out the flames. The fire was eventually put out but unfortunately she had suffered burns.”
Nelly died a few days later in hospital, where Mahlangu was also treated for a week as she too had caught fire when she tried to help the girl.
“I never intended to burn her, as I loved her. I had high hopes for her to one day make something of herself.”
Mahlangu said she has not had peace since the incident as she could not forgive herself for what she had done.
Her employer took the stand to testify in mitigation of sentence and said she had worked for his family for 27 years. Her conduct on the day of the incident was totally unlike her, he said. His family loved her dearly and he suspected that she simply snapped as she was unable to cope with the teenager, who was not an easy person.
Judge Bam said what had happened was a tragic incident which called for a probation officer’s report to assist the court in sentencing Mahlangu.
The case was postponed to December 8.