Judge Robert Henney found Xolile Mngeni, 25, guilty of robbery with aggravating circumstances, premeditated murder and illegal possession of a firearm and ammunition. He was acquitted on a kidnapping charge as this was executed as part of a single chain of events leading up to the murder.
Dewani was killed in Gugulethu on November 13, 2010, and her body found the next day.
"The State has proven its case beyond reasonable doubt," Henney said.
"The case against the accused is overwhelming and the accused could barely avoid the avalanche of evidence from crashing down on him."
Mngeni stood expressionless as the judgment was delivered. His family watched wide-eyed from the gallery above.
Hordes of photographers crowded around Mngeni when he walked back down to the cells, using his walking frame.
One of Anni Dewani's convicted killers presented credible evidence against his alleged accomplice, said Judge Robert Henney. He said Mziwamadoda Qwabe's evidence against Xolile Mngeni, 25, was clear, precise, detailed and chronological.
He said Qwabe came across as intelligent and did not contradict himself on the stand. Henney was reading his evaluation of evidence as part of Mngeni's 60-page judgment.
Mngeni has pleaded not guilty to hijacking, robbing and killing the tourist in Gugulethu, on November 13, 2010. Qwabe was sentenced for the crimes in terms of a plea agreement.
He testified that Mngeni helped him hijack the Dewanis and pulled the trigger on the honeymoon bride. His testimony was the only direct evidence presented in court.
Henney said the evidence of alleged accomplices, like Qwabe, had to be treated with caution and backed up with evidence by other witnesses.
The State called 26 witnesses in total to strengthen its case.
"Much of Qwabe's evidence was corroborated by other witnesses and other evidence," Henney concluded.
He said this was despite Qwabe not being a perfect witness, contradicting what he had said in his statement to police and what he had said on the stand.
"The contradictions are not of such significance that it affected credibility and consistency."
The defence had pointed out that Qwabe originally pleaded not guilty to the murder, citing this as a reason he could not be trusted.
Qwabe explained on the stand that he did not think he was guilty of murder at that stage because he did not pull the trigger.
It was only later that he became aware of the concepts of common purpose and conspiracy to murder.
"In my view, that is a perfectly reasonable explanation considering that Qwabe is not schooled in law," the judge said.
"Even lawyers sometimes get confused about common purpose."
Judgement day for Dewani's alleged killer
Xolile Mngeni, 25, appeared before Judge Robert Henney, and put his head down on his arms to hide from the throng of photographers and video cameras.
Mngeni briefly spoke to his lawyer and then took off his peaked cap as the judge entered. He has pleaded not guilty to hijacking, robbing and killing the tourist in Gugulethu, on November 13, 2010. She was on honeymoon with her husband Shrien at the time.
Henney first gave a background to the murder plot, alleged to have been set up by her husband. The judge said it needed to be remembered that Shrien Dewani had not yet been charged and no direct evidence was presented against him as it was Mngeni's trial. Shrien is in the process of being extradited from the United Kingdom.
Mziwamadoda Qwabe and shuttle driver to the Dewanis, Zola Tongo, had already been convicted of the murder and were sentenced in terms of a plea agreement. Henney said Mngeni was linked to the crime scene by his prints.
"Although initially vehemently denied as the fingerprint of the accused, this fact was later conceded. It can therefore be safely accepted that this was the left palm print of the accused." A total of 26 witnesses were called by the State to strengthen its case.
The defence disputed the evidence of six witnesses. One of the witnesses was the middleman who helped set up the murder. His identity was being protected in terms of a court order.
"Although he gave no direct incriminating evidence against the accused… His testimony is important in completing the overall factual matrix of this case," Henney said.
Qwabe, who considered himself Mngeni's friend and had known him for nine years, also took the stand.
The judge went into detail and read out Qwabe's testimony in full.
The matter continues.