Oscar Pistorius, the South African Olympic and Paralympic athlete who killed his girlfriend, Reeva Steenkamp, by firing four bullets through a closed toilet door, will learn on Wednesday how long he will spend in prison for murder.

In what is likely to be the final chapter in a story that attracted intense worldwide attention, Judge Thokozile Masipa will sentence the former athlete. Most observers expect a lengthy prison term.

Pistorius, 29, who found global fame when he reached the semi-finals of the 200-metre sprint at the 2012 Olympics in London, was initially convicted of culpable homicide and sentenced to five years in prison.

After an appeal by state prosecutors he was convicted of murder, which carries a mandatory sentence of 15 years. He has exhausted almost every legal option available to him.

However, legal experts point out that Masipa has considerable discretion. “I don’t think he will get the 15 years,” Ulrich Roux, a lawyer unaffiliated with the case but who has followed it closely, told AFP.

“His personal circumstances and the disability will be taken into account. One possibility is that part of the sentence may be suspended.”

Others suggested eight years was a likely jail term.

Under South African law, Pistorius, who has been living in his uncle’s large home in a suburb of Pretoria, would be be eligible for parole long before the end of the sentence.

The former athlete has always denied deliberately shooting Steenkamp, a model and law graduate, claiming that he believed a burglar was hiding in the toilet in his home.

In a television interview broadcast last month, Pistorius said that if he “was afforded the opportunity of redemption, [he] would like to help the less fortunate”.

On the third and final day of the sentencing hearing last month, Pistorius, sobbing, hobbled on his stumps across the courtroom to demonstrate his physical vulnerability as his lawyers argued he should not return to jail on account of post-traumatic stress disorder and depression.

A day before, Barry Steenkamp, 73, the father of the victim, tearfully called for Pistorius to “pay for his crime”.

Legal experts say it is extremely unlikely that the sportsman will be able to challenge the sentence he receives, though the state may appeal if it is seen as lenient.