The sister of Oscar Pistorius needed support from a friend during a gruelling day of evidence in court.

Aimee Pistorious listened to painful testimony from witnesses at the murder trial of her brother for killing his girlfriend Reeva Steenkamp on Valentine's Day last year.

They heard a former lover of Pistorius tell how he had cheated on her with Reeva Steenkamp.

Samantha Taylor told North Gauteng High Court: "There was a lot of commotion in our relationship. We were still together but we were having problems."

Taylor also told how Pistorius had fired a gun through the sunroof a vehicle because he had been angry after police stopped him for speeding.

Aimee Pistorius heard another witness talk of his "shock" at the bloody killing of Steenkamp on Valentine's Day, last year. Pieter Baba said he saw Pistorius carry his girlfriend down the stairs of his luxury home, following the shooting.

Baba told North Gauteng High Court: "I was so shocked that I couldn't even think for a few moments. I could see Oscar coming down with Reeva. I was staring at Oscar. I was in such terrible fright."

Oscar Pistorius and Reeva Steenkamp
Oscar Pistorius and Reeva Steenkamp Reuters