Prosecutors closed out the Oscar Pistorius murder trial on Thursday, emphasizing that the acclaimed South African track star intentionally killed his girlfriend last year and should face the consequences.

Pistorius, a famed Paralympic athlete nicknamed the "Blade Runner," fatally shot his girlfriend Reeva Steenkamp on Feb. 14, 2013. The pro athlete pleaded not guilty to first degree murder, arguing that he shot her by mistake because he thought she was an intruder in his home. Prosecutors, however, say he killed her out of rage after the couple had an argument in the wee hours of Valentine's Day.

Proceedings in the high profile trial lasted for over 40 days and included high emotion and media blitz.

During their closing arguments on Thursday, prosecutors painted Pistorius as an unreliable witness who "pre-planned" the murder of his model girlfriend, reports the Washington Post.

Prosecutor Gerrie Nel, who is known for being aggressive in the courtroom, lambasted Pistorius' legal team for presenting two different theories as to why he shot Steenkamp. According to Nel, Pistorius' defense first claimed that the athlete acted in self-defense at what he thought was an intruder in his home, however Nel said that they shifted his defense, stating that he accidentally shot Steenkamp because he was "startled."

"We have two defenses, and we want the court to pick one," Nel said, according to ABC News.

The prosecution added that Pistorius "used well-calculated and rehearsed emotional outbursts to deflect the attention and avoid having to answer questions."

Nel continued to stress on what he called inconsistencies in Pistorius's testimony, castigating the runner as both "vague" and "argumentative. ... His mendacity was striking. ... He was more concerned with defending for his life than entrusting the court with a truthful account of that morning."

During the trial, Pistorius' attorney's argued that he felt vulnerable to a possible intruder because he was not wearing his prosthetic legs at the time and had limited mobility. As a result, he decided to confront the intruder, rather than take flight. Pistorius' defense team reiterated this argument in the closing stages of the trial.

"Although he loathes to be pitied in any way, the hard truth is that he does not have lower legs," said leading South African sports physician Wayne Derman of Pistorius, according to the New York Times. "You've got a paradox -- of an individual who is supremely able and an individual who is significantly disabled," he added.

A verdict could be decided as early as the end of August.

Pistorius "faces 25 years to life in prison if found guilty of premeditated murder," according to The Associated Press.