Oscar Pistorius saw a new side to the lawyer trying to convict him of murder in court this morning when Gerrie Nel went on the attack.

Nel adopted an aggressive demeanour when he cross-examined pathologist Jan Botha, in what was a real contrast to the gentler way in which Nel had behaved until now.

He was previously described as a being a bit of a softie compared to Pistorius's lawyer Barry Roux.

But all that changed this morning when the trial got back underway following a week-long adjournment.

Nel took a hard line by close questioning Botha and picking the pathologist up on each point. At times, it looked like Nel was forgetting the old legal dictum, "cross-examine, do not examine crossly."

During tense exchanges about the bullet wounds Reeva Steenkamp suffered when Pistorius fired four shots, Nel told Botha: "I ask questions and you answer them, not the other way round."

He insisted: "You gave the evidence and I'm testing you. Answer the questions. You cannot say that is unfair."

When Botha asked Nel to clarify one question, the lead prosecutor replied: "I ask questions, you answer. I don't answer your questions."

Nel was told by the judge to "take your time", as Botha was bombarded with questions which appeared to be designed to discredit his version of events.

The stark change in demeanour by Nel was picked up by trial observers, one of whom took to Twitter with this description of his approach:

Another trial watcher gave this opinion on Twitter:

At one point, Botha accused Nel of talking "nonsense," to which Nel replied: I wish I could say nonsense, but I can't, so I won't."

Nel's new approach may be due to it being defence witnesses who are now in the witness stands. Previously, it was prosecution witnesses whom Pistorius's lawyer Barry Roux took a tough line with.

Pistorius denies murder and claims he mistook Steenkamp for an intruder in his luxury home on the outskirts of Pretoria. The prosecution alleges he killed her following an argument.

The trial continues.