Cellphones of the "Sunday Rapist" were used in areas where his alleged victims were abducted, an expert testified on Thursday.
Vodacom employee Petro Heyneke gave this information to the High Court, sitting in the Palm Ridge Magistrate's Court in Alberton, during the trial of Johannes Jacobus Steyn.
She said the GPS signal on both Steyn's mobile phones registered at towers in Danville and Roodepoort on the days and times where two murdered girls were abducted.
The cellphones registered at eight other locations where the other alleged "Sunday Rapist" victims were taken between 2008 and 2011.
Heyneke said the data was "as secure as can be".
"The information is 99.9 percent secure. The system cannot generate information that doesn't exist."
Steyn is accused of murdering teenagers Lazanne Farmer and Louise de Waal.
He is also charged with 11 counts of rape, 10 of sexual assault, 10 of kidnapping, one of attempted sexual assault, one of attempted kidnapping, and two of assault.
He pleaded not guilty to all 37 charges against him.