Closing arguments are expected on Friday in the Protea Magistrate's Court in the murder case against musician Molemo "Jub Jub" Maarohanye and his co-accused Themba Tshabalala.
The two also face charges of attempted murder and driving under the influence of alcohol and drugs.
They were allegedly racing their Mini Coopers in March 2010 when they crashed into a group of school children in Mdlalose Street, Protea North. Four boys died and two others were seriously injured.
At the last court appearance, a video expert testified that a video clip showing Maarohanye and Tshabalala drag racing had not been tampered with.
Ike Motloung, for Maarohanye, explained how the cellphone containing the video was confiscated.
Motloung said the owner of the phone was first allowed to delete items from the phone before handing it over.
Smalberger said police should have used proper methodology.
She said 10 of the 12 videos made on the day of the accident had been deleted. She was able to recover only two.