The trial of a woman accused of murdering a schoolboy came to an abrupt halt yesterday when a teenage witness broke down in tears.

The 16-year-old boy was due to give evidence for the prosecution in the case of Kiahna Trott-Edwards, who is accused of killing Shijuan Mungal by hitting him with a baseball bat.

Matters came to a standstill at about 3.20pm when the witness broke down in front of jurors before he had started giving evidence.

“I can’t do this,” said the boy, before putting his head in his hand and starting to cry.

The jury had previously been told that Ms Trott-Edwards, 32, and Mr Mungal, 16, were involved in an argument on board a bus prior to the fatal attack outside Ms Trott-Edward’s home on Ord Road in Warwick on September 8, last year.

Yesterday passengers on the bus spoke of their shock at the exchange between the pair.

Javon Butterfield, 41, described how a boy (Mr Mungal), who sat next to him on the bus, had urged Ms Trott-Edwards to “shut the f*** up, turn around and sit down” when she had told him to stop cursing and watch his mouth.

Mr Butterfield told jurors he was “shocked” by the boy’s comments towards Ms Trott-Edwards and disapproved of them.

He added: “Her demeanour the entire time was more of an adult scolding a child.”

Mr Butterfield told the court that Ms Trott-Edwards was not threatening, aggressive or looking to pick a fight during the exchange. The jury previously heard that Ms Trott-Edwards got off the bus at the stop before her home, while Mr Mungal got off at the next stop. Both, however, ended up at the same apartment complex in Ord Road.

It is alleged that Ms Trott-Edwards then confronted Mr Mungal in the communal area of the complex and struck him twice with a wooden baseball bat.

Prosecutors say the second blow fractured Mr Mungal’s skull and caused bleeding on the brain that led to his death three days later.

Earlier in the day Tevahn Tyrell, 18, had told the jury he had witnessed the argument between his friend, Mr Mungal, and Ms Trott-Edwards.

He claimed Ms Trott-Edwards had told Mr Mungal: “I will beat you like I am your momma” during the row on the bus. Mr Tyrell told the court that Mr Mungal was a close friend, but that he also knew Ms Trott-Edwards, who he called “Moms”.

He described the mood on the bus as “upbeat” as it left Hamilton Bus Station and said he and his friends were laughing and joking.

The court heard that the atmosphere changed after Mr Mungal “gripped” another boy by the shirt because he thought he was insulting his father’s name.

Mr Tyrell said that Mr Mungal was cursing loudly and that Ms Trott-Edwards told him to “watch his mouth”.

“She (Ms Trott-Edwards) turned around and said there were adults on the bus and that Shijuan should watch his mouth,” said Mr Tyrell.

“Shijuan was the loudest, although everyone at the back of the bus was talking. All of us were talking and cursing but it was nothing over the top.

“She said it in a snappy tone, like she was irritated.

“Shijuan then said, ‘Am I the only one you hear?’ Then it escalated. She said, ‘Don’t you know who I am?’ He replied, ‘You are still going on about me. You are not my momma.’

“Then she said, ‘I will beat you like I am your momma.’

“It was said at high volume and was aggressive.”

Mr Tyrell said the altercation between Mr Mungal and Ms Trott-Edwards lasted around two minutes. He described his friend as “strong-minded” and said that he had been devastated by his death.

Ms Trott-Edwards denies murder.

The case continues.