Oscar Pistorius's defence team on Tuesday picked through the testimony of a police photographer who took images of the bloodied crime scene where the Paralympian shot dead his girlfriend.

Defence lawyer Barry Roux accused police photographer Bennie van Staden of "great disturbance" for moving evidence, and pointed out suspicious timing overlaps that seemed to contradict his testimony.

Van Staden, who often seemed like an accused in the dock himself, moved bloodied towels and a duvet which he said was to check for evidence beneath the objects, but always took pictures of the original scene.

This did not deter Roux, who has hammered away with the argument that police bungles tainted the crime scene so much that the evidence cannot be used against Pistorius.

"How does it happen there was such great disturbance in that scene?" he asked about pictures showing that bedsheets had been moved.

He also said metadata on crime scene photos suggested a "great overlap" in the times photographers documented the scene, contradicting testimony that they worked separately.

"You were taking photos together in the bedroom and bathroom," Roux told police photographer Bennie van Staden, who had earlier testified that he was alone when he documented the bathroom where Reeva Steenkamp was shot dead.

Pistorius, 27, is fighting charges of Steenkamp's premeditated murder, saying he shot the model four times through a locked toilet door thinking she was an intruder.

The athlete sat reading a book in court on Tuesday, occasionally underlining something with a pencil.

His defence team has so far pointed out several police bloopers at the crime scene, including an officer handling the suspected murder weapon without gloves and another stealing from the house.

The defence alleges that changes to the scene make it difficult to prove the sequence of events in the early morning hours on February 14 last year.