Did Reeva Steenkamp flush the toilet before she was shot?

Evidence that Steenkamp flushed the toilet could have undermined both the state and defence cases.

Reeva Rebecca Steenkamp. Picture: Carte Blanche.

PRETORIA - It's emerged that potentially vital evidence was not led in the Oscar Pistorius murder trial, allegedly because it could have undermined the cases of both the state and defence.

A private forensic investigator has studied the crime scene photographs and found that Reeva Steenkamp flushed the toilet before she was shot and killed by the Paralympic and Olympic athlete.

Pistorius was last month found guilty in the North Gauteng High Court of culpable homicide for the 2013 killing of Steenkamp.

The double-amputee has always maintained he fired through the door into the toilet cubicle in the mistaken belief he was defending himself from a burglar.

He is expected to be sentenced on 13 October.

Evidence that Steenkamp flushed the toilet prior to being shot could have cast doubt over the athlete's belief there was an intruder in the house.

But it also would have undermined the state's argument that Pistorius had a fight with his girlfriend, which caused her to flee to the bathroom.

Forensic expert Cobus Steyl says, "Both sides should actually have been allowed. Because it tells you that something has happened with this blood and this toilet, that it was altered by the water from the bowl itself. Any blood experts would immediately have picked that up."