A South African court on Friday increased to 13 years and five months paralympian Oscar Pistorius’s prison sentence for killing his girlfriend.

Prosecutors had argued that the six-year term for murdering Reeva Steenkamp was too short, reports the BBC.

The Supreme Court of Appeal ruled his sentence be increased to 15 years, less time already served.

Pistorius claimed he shot dead Steenkamp on Valentine’s Day in 2013 after mistaking her for a burglar. He was imprisoned last year. Pistorius was sentenced to five years for culpable homicide in 2014.