Samantha Taylor told the High Court in Pretoria that she, Pistorius and his friend, Darren Fresco, were stopped by police for speeding.

An ex-girlfriend of murder-accused Oscar Pistorius on Friday testified that Pistorius had shot through the open sunroof of a car as they drove from the Vaal.

Samantha Taylor told the High Court in Pretoria that she, Pistorius and his friend, Darren Fresco, were stopped by police for speeding.

Pistorius and Fresco stepped out of the car and Pistorius left his gun on the seat.

After checking the car, the policeman told Pistorius that he should not have left his gun on the seat, said Taylor.

"Oscar shouted at the policeman and said he shouldn't touch his gun," said Taylor.

The three of them then drove off.

"Oscar and Darren were irritated and they said they wanted to shoot a robot," said Taylor.

"About two minutes later, Oscar took out his gun and shot through the roof," Taylor, adding that it was through an open sunroof.

As the 20-year-old spoke of the incident, she lifted her right hand in the air and showed a shooting motion.

She told the court that Pistorius and Fresco then laughed about the incident.

Taylor was testifying in the murder trial of Pistorius.

Pistorius shot dead his girlfriend, Reeva Steenkamp, through a locked bathroom door at his Pretoria home.

He alleged he had mistaken her for an intruder.

Taylor, just like Steenkamp, is a blonde with the looks of a model.