Judge Ebenhaezer Jordaan, delivering judgment, said Vincent Mxolisi Mokoena, 29, had intended on killing Spring Mkhatshwa, 28, who met Mokoena regarding the sale of his car.
"The State has proven beyond reasonable doubt that on 8 June last year, you and someone else killed the deceased before robbing him of his vehicle," said Jordaan.
"You are found guilty of murder and robbery with aggravating circumstances."
During the pointing out of the crime scene on 23 June, Mokoena told Captain Adolf Smith that Mkhatshwa was strangled with a seat belt.
"But in court, he denied saying it, blaming Smith for creating the story," the judge said.
On Wednesday, Mokoena said police tortured him to do the pointing out at the crime scene. He said police told him what to do, took photos and that what they wrote in his statement was not what he had told them.
Jordaan on Thursday dismissed the torture claims, stating they were not admissible in court.
Mkhatshwa's body was found along the road to Ohrigstad on 9 June last year.
Mokoena was arrested on 20 June after being found in possession of Mkhatshwa's car in Pretoria on 14 June.
Mokoena had pleaded not guilty.
The matter was postponed to Friday for sentencing.