Steenkamp cousin testifies ahead of Pistorius sentencing

Reeva Steenkamp's father Barry Steenkamp, leaves the High Court in Pretoria, South Africa, Tuesday, June 14, 2016, after Oscar Pistorius's sentencing proceedings. An appeals court found Pistorius guilty of murder, and not culpable homicide for the shooting death of his girlfriend Reeve Steenkamp. (AP Photo/Themba Hadebe) (The Associated Press)

Oscar Pistorius appears in the High Court in Pretoria, South Africa, Tuesday, June 14, 2016 on the second day of the double-amputee runner's sentencing hearing for murdering girlfriend Reeva Steenkamp. An appeals court found Pistorius guilty of murder and not culpable homicide for the shooting death Steenkamp. (AP Photo/Deaan Vivier, Pool via AP) (The Associated Press)

Oscar Pistorius appears in the High Court in Pretoria, South Africa, Wednesday, June 15, 2016 on the third day of the double-amputee runner's sentencing hearing for murdering girlfriend Reeva Steenkamp. Kim Martin, a cousin of Steenkamp has testified in a South African court at the sentencing hearing for Pistorius, who was convicted of murdering his girlfriend in his home in 2013. (AP Photo/Siphiwe Sibeko, Pool) (The Associated Press)

A cousin of Reeva Steenkamp has testified in a South African court at the sentencing hearing for Oscar Pistorius, who was convicted of murdering girlfriend Steenkamp in his home in 2013.

Kim Martin said Wednesday that she and her family are struggling to cope with Steenkamp's death and that every Valentine's Day — the day when Steenkamp was fatally shot — is the "worst day for us."

Martin also criticized Pistorius, a double-amputee Olympian, for agreeing to an ITV television interview that will be broadcast after the sentencing hearing ends this week. She said the former track star should have testified at his sentencing hearing.

South Africa has a minimum sentence of 15 years in prison for murder, although a judge can reduce that in some circumstances.