In later testimony, a police ballistics expert police described how he tried to reconstruct the angle of the gunfire, citing tests that suggest the bullets were fired about 2.2 meters (7.2 feet) from a toilet door in Pistorius' home. The bullets punctured the door, and three of them hit girlfriend Reeva Steenkamp, who was in the toilet cubicle.
Warrant officer Bennie van Staden, a police photographer, took hundreds of photos of the scene, including of blood stains, bullet casings, a gun and a cricket bat found inside Pistorius' bathroom in the hours after the double-amputee Olympic runner shot Steenkamp before dawn on Feb. 14 last year.
Lawyer Barry Roux has challenged previous police witnesses, seeking to uncover contradictions and reported mishaps to support his argument that officers bungled the investigation, an allegation made by Pistorius at the start of the trial when he pleaded not guilty to murder in Steenkamp's killing.
In a painstaking process Tuesday, Roux minutely examined many photos taken by van Staden and another police officer and pointed out that objects at the crime scene had been moved and were in different positions in photos. Roux also used time of day records on the images to show that the two policemen taking photographs were in the same room at points, even though van Staden testified he was working alone.
Pistorius, 27, is charged with premeditated murder for killing Steenkamp, 29. He denies murder and says he shot his girlfriend accidentally, thinking she was an intruder in a toilet cubicle in the bathroom, and says that he struck the toilet door with a cricket bat to get to Steenkamp after realizing what he had done.
Prosecutors charge that Pistorius killed Steenkamp after an argument.
Pistorius' lawyer asked van Staden to explain differences in photographs of position of the 9 mm pistol that Pistorius used to shoot Steenkamp through a closed toilet door, and of a cricket bat that the Paralympian used to hit the door.
"It seems there was movement of the bat" in the interval between two photographs taken by van Staden, Roux said.
"It seems like that," van Staden conceded.
The police photographer also acknowledged that two photographs of the gun indicated that a mat underneath it could have been shifted. Roux said one photo also differed from the other because it showed a wooden splinter on the gun handle.
Capt. Christiaan Mangena, the police ballistics expert, said the bullets were fired at a slightly downward angle and entered the toilet door below the shoulder level of Pistorius, if he were standing without prosthetic limbs. Pistorius said he was on his stumps when he fired. Prosecutors do not dispute the assertion, after initially alleging he was on his prosthetic limbs when he killed Steenkamp.
Mangena said he used thin rods and the beam from a laser mounted on a tripod to try to determine the trajectory of the bullets through the door. He also described entry and exit wounds on Steenkamp's right arm and her head, and bruises on her chest where a "projectile" struck without penetrating.
Associated Press writer Torchia reported from Johannesburg.