Right now the latest from the Oscar Pistorius trial. Another gruesome day in the courtroom and ABC's Matt Gutman is on the scene in Pretoria, South Africa. Good morning, Matt. Reporter: That's right.... See More
Right now the latest from the Oscar Pistorius trial. Another gruesome day in the courtroom and ABC's Matt Gutman is on the scene in Pretoria, South Africa. Good morning, Matt. Reporter: That's right. For the first time in court we saw those gut-churning crime scene photos. From where I was sitting a few benches behind Oscar Pistorius I saw him writhing in his seat then when pictures of his girlfriend's bloody face flashed by on a screen a few feet from his face he became physically ill. This morning for the first time those grisly crime scene photos. His blood smeared prosthetic legs and blood pooled on the bathroom floor where he shot his lover saying he shoot she was an intruder facing murder charges for killing reeva steenkamp, and covering his eyes when the pictures were shown. When a picture of steenkamp's bloody face passed by he started heaving and covering his face with those papers. A mock-up still in court. Pistorius says he smashed through that door with a cricket bat once he realized his mistake. And that bat so closely scrutinized that even the judge wanted a closer look. On Wednesday a prosecution witness dropped what seemed a bombshell. Marks on the door is actually consistent with him not having his legs on and I suspect similar to the location he was when he fired the shot. Seeming to have caught Pistorius in a bold lie. But the defense put the police colonel under a Witt othering assault. He must have had his legs on when he used the cricket bat. That's your version. That's your version. My findings. Would that follow? No. Reporter: Alleged key evidence including that door was mishandled. At times Pistorius passed notes to his lawyer and craned his neck to see that door. That's the door that the prosecution presented today in which Oscar Pistorius used that cricket bat to smash through it. But if you look closely you can see the four bullet holes. Teen camp was hit by three of those four bullets. Pathologists say the 29-year-old model died nearly instantly. The only person that knows exactly what happened that night is in the courtroom Oscar Pistorius. We're told he will testify in the trial. It's very likely he will be the first defense witness called. Sources tell us they want him to set the tone for the rest of the trial. George. Okay, Matt Gutman, thanks. Let's talk to Dan Abrams right now about this. We heard from Matt likely to testify. But Oscar Pistorius, is he in any shape to testify? He better be. When you're talking about a defense that focuses not on did he do it, but why did he do it? What was going on in his head? He becomes an absolutely critical witness and the devil is going to be in the details. Remember, he's already provided an account in connection with his bail application of what he says happened. So he's got to stay consistent with that. My point being this is not going to be easy testimony for him and as a result he better be ready. He's barely able to hold it together in the courtroom. Some suggest he may have some posttraumatic stress syndrome. His lawyers are certainly going to take him through everything. They'll take him through a mock direct examination, cross-examination, make sure he's ready but to some degree they don't have a choice in a case like this. Yes, they could present -- leave the case to the judge. He doesn't have to testify. But because of the facts, because of the type of defense you're talking about here, they've got to figure out a way to get him in shape to testify. Is the decision affected by the fact it is a judge, not a jury? It could be. I don't know that in this case it makes that much of a difference because of the defense but judge versus jury definitely will impact almost every decision being made by the defense and prosecution. But I think in this case they have to. So far has the defense made any headway. The best thick they've gotten the fact his ex-girlfriend testified he was often concerned about possibly intruders, that he would jump up sometimes worried that someone was coming into the house. That's exactly what he is saying happened here. So having someone who is now testified, this is the type of behavior he's exhibited before. I think it's very helpful to him. I think this whole attack on the police is helpful to them, but isn't going to make or break the case.
This transcript has been automatically generated and may not be 100% accurate.