A Muslim cleric, who was among the three people attacked by knife-wielding suspects at the Imam Hussain Mosque in Ottawa, Verulam, jumped out of a second-floor window of the mosque to escape.
At the time, he had already been stabbed several times.
According to Afzal Mitha, who was among the first to arrive at the scene, the attack happened after 14:30.
He said the moulana (Muslim cleric) at the mosque was stabbed multiple times but survived. He and a second victim are in a stable condition in hospital.
"He (the moulana) managed to jump from the second floor of the mosque, while fleeing from the attackers. He told us that the attackers said the mosque was brainwashing people," he said.
A teary-eyed Mitha also told News24 that his friend Abbas Essop had also been stabbed during the attack but that he succumbed to his injuries.
"They tried to stabilise him at the scene but he died while on his way to hospital. His mother is on holiday in Jakarta and now this," the 42-year-old said.
He said Essop is survived by his two children.
Azad Seedat, the mosque's chairperson, told News24 that two people were inside the mosque when the attack occurred.
"The third person went inside to investigate when he heard screams. He was also stabbed and injured," said Seedat.
He said he couldn't rule out that a terrorist-linked group was behind the attack.
"This is a sensitive issue and we can't speculate what happened. But we have complete faith in the police to investigate the motive [for] the attack," he said.
Seedat confirmed that the mosque was attended by Shia Muslims and that its library had been petrol bombed during the attack.
The attack occurred days before the start of the holy month of Ramadaan.
Reaction Unit South Africa (Rusa), a private security company, which was among the first to report the incident, said the suspects fled in a white Hyundai Getz.
Gavin Sigamony, whose house is next to the mosque, told News24 that the attackers had parked their car next to his driveway.
"I didn't suspect anything at the time but I was surprised when I heard what happened shortly after their car left," he said.
KZN police spokesperson Captain Nqobile Gwala confirmed that one person had died.
Police are investigating two counts of attempted murder and one of murder. The motive for the attack is still unknown.