According to BBC, South African athlete Oscar Pistorius is a "broken" man, a defence witness has said at his sentencing hearing. He was convicted of murder at the end of last year for the 2013 murder of his girlfriend Reeva Steenkamp.

He faces a jail term of at least 15 years, but his sentence can be reduced due to time already spent in prison and mitigating factors. The hearing is expected to last all week with a sentence by Friday.

Pistorius, 29, killed Ms Steenkamp in February 2013 after firing four times through a locked toilet door. The athlete has always maintained he believed he was shooting at an intruder.

Psychologist Jonathan Scholtz told the court: "Since the offence he has developed a serious psychiatric condition which has become worse over the past two years - major depression and post-traumatic stress disorder."

During the cross-examination, state prosecutor Gerrie Nel suggested that Pistorius had not shown true remorse but was rather feeling sorry for himself. Pistorius was initially sentenced to five years for manslaughter, but the conviction was upgraded to murder in December following an appeal by the prosecution.

South Africa's Supreme Court of Appeal ruled that the lower court did not correctly apply the rule of dolus eventualis - whether Pistorius knew that a death would be a likely result of his actions. The panel of judges said that it was irrelevant who he thought was behind the door.

Original trial judge Thokozile Masipa will hear arguments from both prosecution and defence this week. The Paralympic athlete may testify. Reeva Steenkamp's father, Barry, who has been absent throughout the case due to poor health, may also appear in court.

Experts say a custodial sentence seems almost unavoidable but factors such as his mental fragility, disability and good behaviour might lead to a reduced jail term. He was released from prison last October after almost a year in jail and allowed to serve out the remainder of his initial sentence under house arrest on his uncle's property in Pretoria.

The South African made history by becoming the first amputee sprinter to compete at the Olympics, in London in 2012. He competed in the 400m, wearing carbon-fibre blades to run against able-bodied athletes.