Oscar Pistorius, the South African Paralympian who was sentenced to five years in prison for the 2013 killing of his girlfriend, applied to appeal to the constitutional court Monday in a final effort to overturn his murder conviction, his lawyer told AFP news agency. Pistorius, 29, was granted bail in December and has been living under house arrest until his next court hearing.

"We have lodged an application for leave to appeal to the constitutional court," Andrew Fawcett, a lawyer on Pistorius's legal team, told AFP. "The application has been served on the director of public prosecutions, and they will now indicate when they will be opposing the application and what the grounds of opposition will be."

Pistorius was charged with the premeditated murder of his girlfriend, South African model Reeva Steenkamp, who was found shot to death in February 2013. The double-amputee Olympic sprinter, nicknamed the "Blade Runner" for his metal running blades, admitted that he did fire the shots that killed Steenkamp through a bathroom door but said he thought he was firing at a home invader. But prosecutors argued that Pistorius shot Steenkamp during an argument.

In October 2014, Pistorius was sentenced to five years in prison for culpable homicide – South Africa’s equivalent to manslaughter – and also given a suspended three-year sentence for an unrelated firearms charge. But South Africa’s Supreme Court of Appeal on Dec. 3 overturned the ruling, finding Pistorius guilty of killing Steenkamp. Pistorius is facing a minimum of 15 years in prison.

After spending a year behind bars, Pistorius has remained under house arrest at his uncle’s home in a suburb of Pretoria. His surroundings are a far cry from prison.  The house is a “three-story mansion, boasting sweeping verandas, landscaped grounds and a swimming pool,” the Telegraph reported.

The International Paralympic Committee ruled that Pistorius will not be allowed to return to the track until 2019, which excludes him from the Rio Games this year. The athlete will be 33 by the time of the Tokyo Olympics and Paralympics in 2020.