Oscar Pistorius wept in court as he was cleared of the murder of his girlfriend Reeva Steenkamp - but will have to wait until tomorrow to find out whether he is guilty of manslaughter.

Judge Thokozile Masipa told the court there was "no doubt" when Pistorius fired his gun "he acted unlawfully", and will rule on Friday whether he is guilty of the lesser charge - known as culpable homicide in South Africa - over the model's death.

At the very end of the hearing, she found the track star acted "negligently", "too hastily", used "excessive force" and failed to take steps to avoid the resultant death.

She stopped short of giving an actual verdict on manslaughter - which carries a maximum sentence of 15 years in prison - and adjourned proceedings.

Earlier, she cleared the world-renowned athlete of both premeditated and second-degree murder.

She told the trial "there are not enough facts" to support the prosecution case that the athlete intended to kill his Ms Steenkamp.

The judge said the charge of premeditated murder relied on "circumstantial evidence" from the State.

"The State has not proved beyond reasonable doubt that the accused is guilty of premeditated murder. There are just not enough facts to support such a finding," she said.

However, just before the court adjourned for the day, Judge Masipa raised the possibility of a manslaughter conviction.

Pistorius (27) was charged with one count of murder, two of illegally discharging a firearm - which is unrelated to the death of Ms Steenkamp - and one of illegally possessing ammunition. He pleaded not guilty to all the charges.

His head down and shoulders shaking, he was visibly distressed and sobbed in court as the judge recounted the events of Valentine's Day last year.

The prosecution had suggested he stormed down his bedroom corridor after his frightened girlfriend in a jealous rage and deliberately shot her through the toilet door in an angry tantrum on that fateful day.

It had pushed for a verdict of premeditated murder which carried a sentence of 25 years in prison.

The double-amputee sprinter insisted he was terrified and felt excessively vulnerable due to his disability and shot Ms Steenkamp in a tragic accident believing her to be an intruder.

Judge Masipa has also highlighted inconsistencies in the athlete's evidence.

Oscar Pistorius: The charges and possible sentences

South Africa has no jury system so Judge Masipa is deciding on the verdicts herself with the help of two assessors.

Proceedings kicked off this morning with the judge outlining the facts of the case before the testimonies of each of the 37 witnesses who gave evidence at the six-month-long murder trial.

Some 21 witnesses testified for the prosecution and 16 for the defence. The judge found discrepancies between witness recollections and phone records, and said she would be relying on the latter.

She described Pistorius as a "poor" and evasive witness who was initially composed, then "contradicted himself" under cross examination.

Judge Masipa said claims by the defence that police contaminated evidence and removed items from the crime scene "paled into insignificance".

She also rejected claims by the prosecution that the relationship between Pistorius and Ms Steenkamp was "on the rocks" - and counter claims by the defence that they were a "loving couple".

"In my view none of this evidence from the State and defence proves anything," she said.

"Normal relationships are dynamic and unpredictable most of the time, while human beings are fickle. Neither the evidence of a loving relationship, nor a relationship turned sour can assist this court to determine whether the accused had the requisite intention to kill the deceased."

Ms Steenkamp's parents - June and Barry Steenkamp - looked on and listened intently to Judge Masipa from a packed public gallery.

Speaking outside court, Pistorius's brother Carl said he is standing by Oscar.