JOHANNESBURG (AP) — A South African appeals court has convicted Oscar Pistorius of murder, overturning a lower court's conviction of the double-amputee Olympian on the lesser charge of manslaughter for shooting his girlfriend to death in 2013.

Justice Lorimer Leach of the Supreme Court of Appeal delivered the ruling by the five-judge appeals court Thursday in Bloemfontein and said the trial court, the North Gauteng High Court, should impose sentence.

Pistorius killed girlfriend Reeva Steenkamp in the early morning of Valentine's Day. He insisted he thought she was an intruder behind a door in his home. The prosecution said Pistorius shot Steenkamp during an argument.

Leach said regardless of who might have behind the door, Pistorius should have known someone could be killed if he fired.