Cape Town – CCTV cameras and vehicle tracking systems were on Thursday lauded as crucial direct evidence that secured a murder conviction against acclaimed artist Zwelethu Mthethwa.Judge Patricia Goliath found him guilty of killing sex worker Nokuphila Kumalo in Woodstock in April 2013.She found it was murder by dolus eventualis (legal intention).While the case was largely based on circumstantial evidence, she said the technology established a strong prima facie case.She repeatedly referred to the CCTV cameras on nearby buildings that night as a "silent witness"."There was direct evidence of his vehicle at the scene as well as the presence of a male with similar features as the accused," she said.Peaceful protestShe could not escape the conclusion that the driver of the one-of-a-kind Porsche 911 Carrera that night was none other than Mthethwa.Mthethwa, dressed in his usual smart suit, appeared expressionless as judgment was handed down. He was later seen cracking a smile.Kumalo was also a silent witness on Thursday, with a commissioned painting of her face taking pride of place during a peaceful protest outside by Sex Workers Education and Advocacy Taskforce members.Artist Astrid Warren used a single available mug shot of Kumalo to create the poster-sized painting.Kumalo suffered both fatal blunt force trauma and liver injury after Mthethwa kicked and stomped on her repeatedly.He was caught on CCTV camera as he parked his Porsche in Ravenscraig Road, Woodstock.No recollection of eventsDuring his trial, he exercised his right to remain silent and did not testify.He also did not hand in a plea explanation.A psychiatrist had told the court that Mthethwa had no recollection of events that night, possibly due to alcohol consumption."A lack of recall does not justify his decision not to testify," said Goliath.She rejected his version of events relayed to a psychiatrist as untruthful and fabricated.She would have reasonably expected Mthethwa to do everything he could to help the police and court determine his movements that night.The court rejected the defence's assertion that the footage showed two separate people, a driver and a kicker, alongside an unidentified woman who also threw a few kicks."The defence's hypothesis is far-fetched since the kicker transformed into the aggressor on the scene."Bail withdrawnKumalo's attacker in the footage was aggressive and was disturbed only by two security guards who approached the gates of a business to investigate what the noises were.It was thanks to a quick-thinking security guard, who noted his vehicle and wrote down part of his registration, that police were able to track Mthethwa down.Mthethwa's customised "Basalt Black" vehicle, the only one with black wheels in Cape Town at the time, also placed him in a tricky position.Goliath said the Porsche dealership staff member who sold the vehicle was an excellent witness."He spoke about the tail lights and the coupe shape at the back. He said it had a distinguished silhouette and its shape is iconic."The defence asked that his R100 000 bail be extended after the State said it would not object.The matter was postponed until March 29 for sentencing proceedings.