The love life of running star Oscar Pistorius and model Reeva Steenkamp in the weeks leading to her death has been picked through in court.

Chief prosecutor Gerrie Nel has told the court "This wasn't a normal relationship - this relationship ended in death".

In summing up his case against Pistorius, he told how the pair had exchanged messages proving their romance had "ups and downs" and added: "90% of the time he made her happy, but 10% of the messages she was unhappy. And seven days later she was dead".

Mr Nel has also accused the athlete's lawyers of presenting a dishonest defence against the murder charge. He made the allegation in his closing speech against the athlete who shot dead Ms Steenkamp through a toilet door at his home in February 2013.

Mr Nel said a criminal trial was a "blunt instrument for digging up the truth," adding Pistorius' lawyers argued the athlete acted in self-defence as he feared an intruder was in his house, but also suggested he shot Ms Steenkamp because he was 'startled'.

"It's two defences you can never reconcile" said Mr Nel, who went on to accuse Pistorius of being an "appalling, vague" and "deceitful" witness.

Pistorius was "more interested in defending his life than telling the truth," Mr Nel said. "His story is so improbable it's a clear indication of his mendacity".

Mr Nel used Pistorius' career as an athlete as a metaphor for the trial, which the prosecution suggested was like a race with Pistorius holding the "baton of truth".

"You started the race by giving evidence" said Mr Nel, adding "You dropped that baton. You cannot complete the race".

The judge has made a rare interjection to question whether Reeva's Whatsapp messages - some saying she was unhappy - could be relied on as evidence.

As Mr Nel summed-up some 100 pages of evidence submitted to the court last week, Pistorious occasionally shook his head in disagreement and held his head in his hands.

Reporter Alex Crawford at the court in Pretoria said "It was like watching flashbacks from a horror film. Gerrie Nel picked up what he believed to be (Pistorius') most devastating moments in court.

"He drew a very ugly picture of Oscar Pistorius, the man and the personality. A hero who had fallen so low, in the view of Gerrie Nel".

Prosecution and defence lawyers will sum up their cases over the next two days - in a final attempt to convince judge Thokozile Matilda Masipa before she reaches her verdict, expected in around two weeks' time.

Pistorius (27) faces a minimum of 25 years in prison if found guilty of premeditated murder. He could also be convicted on lesser charges, such as culpable homicide or murder without premeditation.

The prosecution says Pistorius intentionally shot Ms Steenkamp in anger after they quarrelled. His defence insists he fired by mistake, thinking an intruder was in the toilet and that Ms Steenkamp was in the bedroom.

Ms Steenkamp's parents are in court listening intently to the closing speeches. It is the first time Ms Steenkamp's father Barry Steenkamp has attended court since the trial began.

The hearing in Pretoria has resumed after it was put on hold last month after hearing from 37 witnesses.

Originally published 07:39