Pretoria - A 19-year-old North West youth told the High Court in Pretoria on Tuesday how he and two of his school friends had used dagga before bludgeoning and strangling a 56-year-old man to death on his farm near Brits.

Judge Tshifiwa Maumela convicted Ernest Mashudu Nevhulamba, of the Bokfontein squatter camp near Brits, of murdering and robbing Charles Beresford Pretorius Jobling on his farm near Hartbeespoort dam on August 31, 2012.

Nevhulamba admitted that he and two school friends had murdered the 56-year-old Jobling in his home before dumping his body in a nearby river.

He also admitted that he had robbed Jobling of his cellphone, bakkie, wallet and ring.

Nevhulamba was caught after he and his cohorts were involved in an accident with Jobling's bakkie and were taken to hospital. The police traced back the vehicle to Jobling after the accident but his body was only discovered by passersby a day later.

One of Nevhulamba's former school friends, Tshepang Mosito, at first also pleaded guilty to the murder and robbery, but later told the court he wanted to change his plea as he had not realised he would go on trial if he admitted guilt.

Tshepang Mosito's trial was separated from that of Nevhulamba. He will go on trial along with Tshego Mosito and David Thebereng - who denied guilt - in May 2015.

The five were all pupils at the Schaumberg school at the time.

Jobling was a descendant of the Voortrekker leader Andries Pretorius and still lived on a portion of the original Pretorius farm.

He was a noted historian and was the chairman of the Hartbeespoort Environment and Heritage Association.

Nevhulamba said in his plea explanation he, Tshepang and David had smoked dagga before David suggested that they must go to the place where he lived to borrow a car from a white man.

The white man was watching television when they entered his house, where David grabbed the man by his neck and choked him.

Tshepang also choked the man with an electric cord and Nevhulamba took an iron bar and hit the man on the head.

David then searched their victim and took his wallet and gold ring, whereafter they loaded Jobling's body into his bakkie and dumped him in the river.

Afterwards, the group picked up some friends and had beer at a tavern.

They were involved in an accident with Jobling's bakkie the next day while on their way home.

Nevhulamba said he realised he had acted unlawfully, took full responsibility for his actions and was remorseful.

His trial was postponed to November 13 for a pre-sentence report.