South African paralympic star Oscar Pistorius pleaded not guilty to charges that he murdered his girlfriend, model and reality television star Reeva Steenkamp, last year.

On Valentine's Day last year, Pistorius pointed a gun at his bathroom door and fired four bullets into it. The defense claims that Pistorius believed an intruder had broken into his home, and that he was merely defending himself when he shot his girlfriend. They claim he felt vulnerable because he did not have his prosthetic legs on, and that the death of Steenkamp was a "tragic, terrible mistake."

The trial opened today with a neighbor who testified that she heard "blood-curdling screams" coming from Pistorius's house the night of the killing.

"Just after 3, I woke up from a woman's terrible screams," Michelle Burger testified. "Then I also heard a man screaming for help. Three times he yelled for help."

Pistorius is charged with premeditated murder, a crime that carries a mandatory life sentence in South Africa. He could also be found guilty of "culpable homicide," a crime based on negligence, for which he could receive a sentence upwards of 15 years.

His fate will be decided by Judge Thokozile Matilda Masipa -- the second black woman appointed to the South African bench since the end of apartheid -- instead of a jury, as jury trials were abolished in South Africa in 1969.

Last Tuesday, Judge Dunstan Mlambo ruled that he would allow devices "to obtain a video and audio recording" of the trial. However, no one who testifies and wishes not to be on camera will be filmed.

This is the first trial in South Africa to be broadcast live.

Watch a live feed of the Pistorius murder trial via The Telegraph below.

[Image via AFP]