Former star athlete Oscar Pistorius will likely return to jail, after an appeals case resulted in a murder conviction for the shooting death of his girlfriend Reeva Steenkamp.

The Washington Post reports Oscar Pistorius was found guilty of murder by the South Africa's top appeals court, overturning an earlier charge of culpable homicide.

The amputee Olympian, known worldwide as Blade Runner, will now face a minimum sentence of 15 years, though this may be reduced due to time spent, as in addition to the accused's disabled status.

Pistorius, who is currently on house arrest in his uncle's mansion in Pretoria, was not present in court when the verdict was read. He had been paroled less than a year into his 5-year sentence, when he was previously convicted on a charge equivalent to manslaughter.

"We have taken note of the judgment that has just been handed down by the supreme court of appeal," said Pistorius' family in a statement. "The legal team will study the finding and we will be guided by them in terms of options going forward. We will not be commenting any further at this stage."

According to the New York Times, the appeals court sided with the state prosecutors who argued the original conviction was based on a misinterpretation of laws and disregard of critical evidence.

South African law allows for state prosecutors to appeal a verdict to a higher court, who can overturn a verdict or sentence independent of a jury system.

"There's nothing untoward in that," said criminal defense lawyer Marius du Toit. "What you often find is that they would disagree with a ruling and say, 'This decision is clearly wrong.' They're not pronouncing on the bona fides of the judge. It's just part of the checks and balances you would want in a legal system."

The case saw international attention after Pistorius shot and killed Steenkamp through a locked bathroom door on Valentine's Day in 2013. Pistorius claimed that he had thought Steenkamp was an intruder, an account previous Judge Thokozile Matilda Masipa said "could reasonably be true."

However, Judge Eric Leach of the Supreme Court of Appeal said Judge Masipa misinterpreted a legal concept known as "dolus eventualis" saying that Pistorius had to have known that whoever was on the other side of the door could have died due to his actions.

Pistorius is expected to return to court for sentencing later this year.