Oscar Pistorius's Murder Trial Begins

Track star Oscar Pistorius pleaded not guilty to the murder of his girlfriend Reeva Steenkamp, as his trial got underway this morning in Pretoria, South Africa.

Pistorius is accused of killing Steenkamp in the early morning of Feb. 14, 2013, at their home in Pretoria. Pistorius fired four shots through a locked bathroom door, hitting Steenkamp three times. The prosecution claims it was deliberate, and from opening statements today intends to show that Pistorius shot her after an argument. Pistorius claims he did not realize Steenkamp was in the bathroom, and believed he was firing on an intruder.

Interestingly, the intended target does not matter. While the prosecution hopes to prove Pistorius knowingly killed his girlfriend, an "error in persona" doesn't materially change the charge of premeditated murder—Pistorius could still be guilty if he is found to have intended to kill an intruder. Premeditated murder carries a minimum sentence of 25 years.

The case promises to be a long one. The state's list contains 107 witnesses, and even if all are not called, it will be months before a verdict is rendered. Pistorius's fate will not be in the hands of a jury; instead, it will be decided by a judge with the help of two "assessors."

Today's first witness, a neighbor, told the court that he heard a woman's "bloodcurdling screams," and one gunshot, followed by a pause, then three more in quick succession.

If you're interested, ESPN3 is streaming full, 24-hour coverage of Pistorius's trial.