South African prosecutors announced Monday that they will appeal the sentence and conviction handed to Oscar Pistorius, who was found guilty of culpable murder and sentenced to five years in prison last week.

In September, the Paralympic athlete known as the "Blade Runner" was found not guilty of murder in the 2013 shooting death of his girlfriend Reeva Steenkamp. The Olympic champ argued that he shot her on Feb. 14 by mistake because he thought she was a home intruder.

Although Judge Thokozile Masipa acquitted him of murder charges, she found him guilty of culpable homicide, a lesser charge that is comparable to manslaughter. She then sentenced the double-amputee runner to five years at Pretoria's Central Prison, but he is only required to serve 10 months behind bars before he can be moved to community supervision or house arrest.

National Prosecuting Authority spokesman Nathi Mncub posted on Twitter that the organization "will be appealing both the conviction and sentence."

"The appeal on conviction is based on the question of law," the national prosecuting spokesman said, according to BBC News.

"The prosecutors are now preparing the necessary papers in order to be able to file within the next few days," said Mncube in a statement.

Mncube added that fiery prosecutor Gerrie Nel and his aides "had been studying the judgment, doing research and consulting legal experts to establish if there were sufficient grounds to lodge appeals," reports The New York Times.

"The prosecutors are now preparing the necessary papers in order to be able to file within the next few days," Mncube said, reports the South African Press Association, according to The New York Times.

During a recent interview with The New York Times, June Steenkamp described Pistorius as "pathetic", "moody," "gun-toting" and "possessive".

She also said she rejects his apology and does not believe his version of events.