Sentencing proceedings in the trial of sexual predator Collan Rex are nearing a conclusion, with the prosecution and the defence expected to present closing arguments on Thursday.

Rex, 23, was found guilty of 144 counts of sexual assault and 12 counts of sexual assault in September 2018.

A number of boys from the prominent Johannesburg school, most of whom were  boarders, testified about how Rex had choked them during 2016.

Others testified that he had touched their genitals.

In his defence‚ Rex said he had meant no harm choking the boys - "it was merely horseplay," he argued.

The South Gauteng High Court, sitting at the Palm Ridge Magistrate’s Court, has heard evidence by the prosecution in the sentencing proceedings.

A report from a probation officer, presented on Tuesday, recommended that Rex be sentenced to a direct jail term.

The court also heard statements from victims on how the assaults had affected them. 

On Wednesday, the court heard from the matron at the school, Mariolette Bossert, about how the behaviour of a number of boys, most of whom were boarders, changed drastically following the assaults in 2006.

She described one of the boys as a leader when she first met him in 2016. “He was the most amazing child, a leader,” she said.

But, since the revelations of sexual assaults, the boy was now under suicide watch after attempting to take his own life in 2017.

Bossert said the boy wrote his final examinations this year from a psychiatric hospital in the North West. He started smoking marijuana after the incident.

“He would walk by himself to Hillbrow to buy drugs. He started drinking,” said Bossert.

She also described how another boy had tried to report Rex’s behaviour to the head of boarding at the school, who advised the boy to “stay away from Rex”. She said the boy was now seeing a psychologist once a week.

Bossert described how one boy choked by Rex had told her that he had passed out from  "sunstroke". After the incident, he attended two hearings at the school for drug use. “He wanted to drop out of school.”

The court earlier heard testimonies from the boys’ parents on how the assaults had changed their children's lives.