Monday, sentencing began for former paralympian Oscar Pistorius. He's facing up to 15 years in prison, for murdering his girlfriend Reeva Steenkamp. Both sides are making their argument to influence the sentence. And the defence has begun - by claiming Pistorius has major depression.

A broken man who should be hospitalised rather than jailed. That's how the defence team described Oscar Pistorius. Johann Scholtz, a psychologist, says he is not fit even to testify.

"Since the offence he has developed a serious psychiatric condition which has become worse over the past two years," said Dr. Johann Scholtz defence witness.

Pistorius shot his girlfriend Reeva Stenkaamp in 2013. At the time he said he mistook her for an intruder - and shot four times through the door of the bathroom where she was hiding.

Chief prosecutor Gerrie Nel disputes that Pistorius is too traumatised to testify. Pistorious, he said, just recently gave an interview to British TV.

Nel also said state experts found Pistorius was aggressive in prison - something the defence witness had not mentioned.

"Why did you not include his aggressive and verbally violent interaction towards officials, why didn't you mention that in your report, are you saying it never happened? " said Gerrie Nel lead prosecutor.
 
"It is possible that it happened I accept that if she says that it happened it happened," said Dr. Johann Scholtz - defence witness.

"Why did you not tell this court about it? " said advocate Gerrie Nel - prosecutor.

"Because I deem it to very unscientific," said Dr. Johann Scholtz - defence witness.

Pistorius looked dazed, as he did for much of his trial. The prosecuting authority is determined to push for the maximum sentence - 15 years.

"We will argue for the imposition of the harshest possible sentence ever that is prescribed by the law but it is not within us to impose the sentences, it's in the discretion of a presiding officer. We accept that if she finds that there are compelling answer substantial circumstances to deviate from the prescribed minimum sentence, she can deviate," said Luvuyo Mfaku national prosecuting authority.

Sentencing is due to run through the week - with more witnesses for the defence and prosecution before the judge hands down her decision.

Reeva Steenkamp's father is expected to testify for the first time in the trial. Barry Steenkamp was previously too unwell to even attend the proceedings. He is now expected to plead with the court to ensure that Oscar Pistorius receives a harsh sentence.