By Bronwyn Gerretsen

Faced with numerous death threats, concerned parents Johan and Magdelena "Riekie" Lotter feared only for their three children's safety.

The Durban couple were so concerned they hired private investigator Brad Nathanson to investigate.

Last Saturday the couple were bludgeoned to death in their home.

The following day police arrested the Lotters' 20-year-old son Hardus and 26-year-old daughter Nicolette.

Detectives also arrested Nicolette's boyfriend Mathew Naidoo, 21.

The Lotters have another daughter, who is studying in Stellenbosch.

The three alleged killers appeared in the Pinetown magistrate's court on Wednesday.

They allegedly confessed to the murders before their court appearance this week.

It is believed Hardus and Nicolette beat each other up to corroborate their tales of being accosted and attacked by groups of unknown men and told to deliver death threats to their parents.

The two had apparently planned to kill their parents by injecting air into their veins to induce heart attacks.

But their plans went awry.

As they allegedly attacked Magdelena, who was in the kitchen at the time, the two of them and Naidoo struggled to find her veins so they stabbed her to death instead.

Their father was apparently asleep when the three accused entered his bedroom.

They allegedly hit him over the head with a piece of wood and then strangled him to death with electrical cord cut from the television set.

Nathanson and other sources believe Naidoo was the ringleader.

The three met 18 months ago and Naidoo and Nicolette became romantically involved almost immediately.

Johan Lotter was horrified. He didn't approve of Naidoo and didn't want him in his home.

It took just a few months for Naidoo to turn the siblings' minds around and their life-long teachings upside down.

Nathanson said: "He made the children believe their parents were scum. Whatever they had been taught by their parents, he would teach them the opposite. He was an absolute fanatic".

Johan Lotter approached Nathanson about two weeks ago after receiving several death threats in the form of SMSes and letters.

He also told of Hardus and Nicolette being accosted and attacked by a "group of white guys" who gave them the threats verbally and told them to pass the message on to their parents.

Nathanson said Lotter had had suspicions that Naidoo was responsible for the threats.

"I said to him 'my worry is that because of the intent, it has got to be someone close to you. They know too much about you'. But he could not think of anyone who would want to kill him," he said.

International Mobile Equipment Identity searches on the cellphones used to send the threats and phone calls to these numbers proved fruitless.

The Wednesday before the murders, Lotter received another letter which was extremely derogatory about him and his wife and how they had brought up their children. In it, as in most of the other threats, there were references to verses in the Bible.

Nathanson, who was in Cape Town at the time, told Lotter to "think very hard" about whether there was someone he had angered over the past few years.

Lotter could not. His reply was: "Whatever I have done I can answer for, but no-one must hurt my kids."

Nathanson's work colleague, Rob Griffiths, collected the letter from Magdelena on Thursday to take it for forensic analysis. They were due to meet and discuss the matter on Monday. However, the couple were killed on Friday.

At the time of his arrest, Naidoo was said to have appeared smug and allegedly said that the Lotters had deserved to die. He also seemed proud of the fact that a private investigator had not been able to stop the crime.

Media reports have quoted sources close to the investigation as saying that Naidoo claimed to have been "God's messenger" and the "third son of God".

Before the three confessed to the murders, Hardus allegedly told police he was accosted by two balaclava-clad men who took his cellphone and locked him in his bedroom.

Nicolette claimed she came home later and found the bodies of her slain parents. She then allegedly unlocked the door and let her brother out of the room.

The three will appear in court again on Thursday, presumably to plead.