Reeva Steenkamp's cousin has told Oscar Pistorius' sentencing hearing that the athlete must "pay for what he's done" and that she did not believe the sincerity of his courtroom apology to the family of the woman he killed.
Kim Martin, while giving testimony on the impact of Ms Steenkamp's death on her family, said they are "not seeking revenge" for the fatal shooting, but that Pistorius needs "sufficient punishment".
At the court in Pretoria, Judge Thokozile Masipa is listening to testimony from witnesses before deciding what punishment the double-amputee Olympian must serve after convicting him of culpable homicide for shooting Ms Steenkamp at his home last year.
Pistorius' defence lawyers have argued for a sentence of three years of house arrest. Prosecutors say the former star athlete and Paralympic champion should be sent to jail.
Ms Martin told the court: "We just feel, to take somebody's life, to shoot somebody behind the door who is unarmed, who is harmless, needs sufficient punishment."
Pistorius was acquitted of murder for the killing, but was found guilty of the lesser crime of negligent killing.
Judge Masipa has wide latitude when deciding on a sentence for culpable homicide, and could order a suspended sentence and a fine, house arrest, or send him to prison for up to 15 years.
Defence lawyers have argued for a sentence of three years of house arrest with community service.
In the first part of the sentencing hearing, they called a psychologist and social workers, who said Pistorius should not go to prison because of his ongoing emotional suffering.
They also said his disability as a double amputee who needs prosthetic legs would leave him vulnerable in jail.
Chief prosecutor Gerrie Nel has called suggestions of a house arrest sentence "shockingly inappropriate" and wants Pistorius to be sent to prison.
Ms Martin said a prison sentence would be appropriate for Pistorius and that she understood the rehabilitation program in jail to be humane and dignified, contrary to allegations by one of the social workers who testified for the defence.
In her sometimes emotional testimony, Ms Martin said many people had suffered because of Pistorius, including his own family, and that a sentence that excludes jail time would encourage the athlete to "feel within himself that what he's done is all right".
Zach Modise, the acting national commissioner for correctional services, testified after Ms Martin, saying that the South African prison system compared favourably with prisons he had visited in Britain and the United States.
He acknowledged problems such as overcrowding and gang activity, but said officials had made progress in combating those problems and that some prison facilities can cater to disabled criminals, including Pistorius.
Mr Modise said: "We will be able to accommodate him."
However, defence lawyer Barry Roux referred to reports of an increase in alleged torture in South Africa's prison system.
He also said an imprisoned gang leader allegedly said Pistorius would be under threat if he is incarcerated. Mr Modise said that he was not aware of any threat.
At the beginning of Thursday's proceedings, Mr Nel congratulated Judge Masipa on her 67th birthday, and people in the courtroom applauded.
Judge Masipa smiled, thanked Nel and then the testimony began on the 47th day of proceedings in the case, which began more than seven months ago.
The sentencing hearing is expected to take up to a week.