Oscar Pistorius hugs his sister Aimee in court in Pretoria, South Africa, today. He is on trial for murder.

PRETORIA, South Africa — Reeva Steenkamp was standing in a toilet cubicle and facing the closed door when she was hit in the right hip by the first of four hollow point bullets fired at her by Oscar Pistorius, a police ballistics expert testified today at the double-amputee Olympic runner’s murder trial.

Steenkamp then fell back onto a magazine holder in the cubicle and was struck in the right arm and head by the last two shots fired by Pistorius with his 9 mm pistol through the door. Pistorius’ girlfriend crossed her arms over her head to protect herself, Capt. Christiaan Mangena said, when she was hit in the arm and head. He testified that he believed the second bullet shot missed Steenkamp and ricocheted off a wall inside the cubicle and broke into fragments, which caused bruising on her back.

Mangena concluded through his analysis of the shooting scene and wounds on Steenkamp’s body from post-mortem photographs that one of the final two bullets went through Steenkamp’s left hand before penetrating her skull as she held it over her head. The policeman said he couldn’t determine the order of the last two shots.

Pistorius, 27, is charged with premeditated murder in Steenkamp’s shooting death on Feb. 14 last year and faces 25 years to life in prison if convicted. He says he shot Steenkamp, 29, by mistake through a locked door in his bathroom because he thought she was a dangerous nighttime intruder.

Pistorius says Steenkamp went to use the toilet during the night without him knowing, but prosecutors maintain he killed her after a loud argument that caused her to possibly flee and hide in the toilet area.

June Steenkamp, Reeva’s mother, also was in the courtroom and occasionally glanced at photos of the bloody scene of her daughter’s shooting before looking away.