Oscar Pistorius' lawyer said the South African Supreme Court of Appeal ignored the double-amputee's vulnerability when it overturned a manslaughter conviction, declaring him guilty of murder for killing his girlfriend Reeva Steenkamp in 2013.

In a request to South Africa's Constitutional Court to hear an appeal of the murder conviction, lawyer Andrew Fawcett said Pistorius was on his stumps, which made him anxious, when he fired. He said the appeals court ignored the trial court's finding that Pistorius believed his life was in danger.

Fawcett also challenged the appeal court's conclusion that the athlete knew he would kill someone when he fired into a toilet cubicle.

Pistorius is under house arrest while the Constitutional Court decides if it will hear the case. Sentencing is scheduled for April 18.