"Blade Runner" Oscar Pistorius was found not guilty of the murder of girlfriend Reeva Steenkamp Thursday as a South African judge dismissed the most serious charges against him.

"The state clearly has not proved beyond reasonable doubt that the accused is guilty of premeditated murder," Thokozile Masipa said, before dealing with the lesser charge of culpable homicide -- also known as manslaughter.

"Viewed in its totality the evidence failed to establish that the accused had the requisite intention to kill the deceased let alone with premeditation," said Masipa.

"Clearly he did not objectively foresee this as a possibility, that he would kill the person behind the door," she said as she later dismissed the lesser charge of common murder.

The 27-year-old sat in the dock bowed and burying his head in his hands after the finding was made.

Pistorius was charged with one count of murder and three firearms offences over the killing on Valentine's Day 2013.

He could still be found guilty of culpable homicide, carrying anything from a suspended sentence to a lengthy prison stretch, or he could be acquitted.

A charge of premeditated murder would have meant a life sentence in South Africa's notoriously brutal jails.


'Evasive'

Pistorius had grimaced and sniffled as he watched Masipa call Pretoria's High Court to order and read her verdict.

Both defence and prosecution agree Pistorius killed the law graduate and model when he fired four shots through a locked toilet door in his upmarket Pretoria home.

But the sprinter says he thought he was shooting at an intruder while Steenkamp was safely in bed.

The prosecution says he killed her in a fit of rage after an argument.

Judge Masipa moved quickly through her judgement, rejecting state evidence that pointed to an argument between the couple.

"Neither the evidence of the loving relationship or a relationship turned sour can assist this court to determine whether the accused had the requisite intention to kill the deceased," she said.

The judge also reviewed evidence by neighbours who testified of hearing shots and screams, saying many "had their facts wrong".

She said huge media coverage of the case could have affected some witnesses.

"I am of the view that they failed to separate what they knew personally or what they heard from other people or what they gathered from the media," she said.

But Masipa also said Pistorius himself was "evasive" on the stand, and that his evidence showed "a number of defences, or apparent defences".

"The accused was a very poor witness," she said.


'Reality show'

The verdict is the climax of a six-month murder trial that has cast a harsh spotlight on the fallen hero's private life.

Full of high drama, the trial has fed intense media interest worldwide, with live broadcasts veering into the realm of TV reality shows.

During proceedings Pistorius has broken down, weeping and at times vomiting as he heard how the 29-year-old blonde's head "exploded" like a watermelon under the impact of his hollow-point bullets.

On Thursday a man selling papers on a nearby street corner said he couldn't keep up with the demand. "Maybe you can come later," said Thomas Mdlule, the 29-year-old vendor, rushing to count out change for his customers.

Thursday's verdict is unlikely to be the end of the case.

There will be more courtroom arguments before a sentence is handed down and, most likely, an appeal to a higher court.

"The trial is the first leg of a multi-legged legal process. It's just the beginning," said lawyer David Dadic.

Whatever happens, Pistorius's glittering sporting career is likely to be over.

Once a poster boy for disabled sport, he has been stripped of lucrative endorsement deals by global brands and has withdrawn from all competition.