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.