[Cooper:] The "Crime and Punishment" tonight, the Jodi Arias murder trial. She is accused, of course, of shooting ex-boyfriend Travis Alexander, stabbing him dozens of times, cutting his throat. Now if she is found guilty, she could be sentenced to death. Today the defense relied on expert testimony. More on that in a moment. Arias herself, as you know, spent 18 days on the stand, testifying she doesn't remember much of the attack, which she calls self-defense. The prosecution calls it premeditated murder. Her testimony ended in a face-off with the prosecutor. Here's Randi Kaye in Phoenix.
[Unidentified Female:] Please stand for the jury.
[Randi Kaye, Cnn Correspondent:] On her final day on the stand, Jodi Arias was schooled in mathematics. Do the math, the prosecutor attempted to show. Her story doesn't add up.
[Juan Martinez, Maricopa County, Arizona, Prosecutor:] At some point in your life, people have watches, right? You know about time. And you know that movement takes time, don't you?
[Kaye:] Martinez says Arias simply would not have had enough time given the evidence to first go searching for the knife she used to stab Travis Alexander nearly 30 times and slit his throat. He says she must have had the knife with her in the bathroom when she was taking these digital pictures of a naked Alexander in the shower.
[Martinez:] It would have taken time to actually look for it, wouldn't it?
[Jodi Arias, Accused Of Murder:] I guess under that theory.
[Martinez:] Sure under that theory. It would take time, right?
[Arias:] Yes, I guess.
[Kaye:] To prove his theory of premeditation, the prosecutor showed these two photographs, taken just 62 seconds apart, according to their time stamps. Arias says this accidental photo of the ceiling was taken after she dropped Alexander's camera, when he was still alive. That's when she says he lunged at her.
[Martinez:] In the 62 seconds between that photograph and Exhibit 162, you are body slammed, you get away, you get the gun, you shoot him, and then after you're able to get away, you go get the knife and he ends up at the end of the hallway, all in 62 seconds. That's what you're telling us?
[Arias:] No, that's not what I'm saying.
[Kaye:] Regardless of what Arias is saying, the photo time stamps say something else. In this second photo taken just over a minute later, Arias' foot is seen next to Alexander's bleeding body in the bathroom. By now he's been stabbed and shot. With just 62 seconds between the photos, have been enough time to support Arias' scenario that a chase and a struggle occurred?
[Arias:] I don't know.
[Kaye:] More than a month into her trial, on her 18th day on the stand, Jodi Arias offered a brand new scenario for how the knife came into play. Listen to this.
[Martinez:] You needed to go get that knife at that point, correct?
[Arias:] No, it's possible Travis grabbed the knife first.
[Martinez:] You never told us that he had any knife there, did you?
[Arias:] No. I wasn't asked.
[Kaye:] Jury members also had questions for Arias about the knife. Seems they, too, were trying to make sense of her changing stories.
[Judge Sherry Stephens, Maricopa County Superior Court:] You said you remember putting the knife in the dishwasher after killing Travis. But you also say you don't remember anything after dropping the knife on the bathroom tile. Which is correct?
[Arias:] I have a vague memory of putting a knife in the dishwasher. I'm just not sure if that's the memory from June 4th.
[Kaye:] And there were more questions about the gun Arias used to kill Alexander. Was it in a holster or not when she said she grabbed it out of Alexander's closet? Just last week she told the jury she believes the gun had been in a holster. Now suddenly, she's not so sure. And this is key because the state believes she brought a gun with her to kill Alexander and never really grabbed the gun from Alexander's closet. [voice-over]: Arias seemed to get tripped up again on this question about whether or not the gun was loaded.
[Juan Martinez, Maricopa County, Arizona, Prosecutor:] Did you tell the jury when you were talking about the attack in response to one of their questions that you believed the gun was unloaded? Do you remember saying that? Yes or no. That's all I'm asking. Yes or no. Do you remember saying that?
[Arias:] I don't know.
[Kaye:] After that, the prosecutor let her have it.
[Martinez:] What were you going to do with the gun, throw it at him?
[Cooper:] Randi joins me live from outside the courthouse in Phoenix. The defense put an expert on the stand today to try to explain her memory loss. How convincing was he?
[Kaye:] Well, Anderson, as you know, memory loss for Jodi Arias has been such an issue at this trial. She says she remembers shooting Travis Alexander, but she doesn't remember anything after that. She doesn't remember stabbing him 29 times or cutting his throat and she doesn't even remember what she did with the knife. So today the defense put a psychologist on the stand to try and explain that, and he said that amnesia can occur after acute stress. He said he met with Jodi Arias 12 times. He said he believes she has PTSD and he has no idea when her memory will actually return. It may come back in bits and pieces, which she says it's already doing. But here's the thing, the defense lawyer asked him could anyone fake this, could she be faking this, and the psychologist said absolutely not. You can't fake this, you have to know the ins and outs of the tests they run for this, you would have to know the answers for the tests they do. So it's impossible, he said that Jodi Arias is actually faking a memory loss Anderson.
[Cooper:] Well, we'll see what the jury decides. Randi, thanks very much. Let's dig deeper now. Our legal panel joins me, senior legal analyst Jeffrey Toobin and criminal defense attorney, Mark Geragos, co-author of "Mistrial, An Inside Look at How the Criminal Justice System Works and Sometime Doesn't." So Jeff, the prosecutor made a lot of the 62 seconds that the crime would have had to have been committed in, saying basically it was impossible. Why was that such an important point?
[Jeffrey Toobin, Cnn Senior Legal Analyst:] Well, because it's the key to her whole story. She has an explanation of how this crime unfolded, and the photographs are weirdly, that's one of just the weirdest things about this case, are basically a time stamped version of how the case unfolded. Her version does not seem to make any sense. I thought Martinez was so effective today in pointing out just how absurd it is that she could have done all of that in 62 seconds.
[Cooper:] Mark Geragos, what did you think of the expert that the defense had talking about memory loss? I just want to play some of what he said for our viewers who didn't watch it.
[Richard Samuels, Forensic Psychologist:] People who suffer from stress producing trauma will frequently not recall what happened for a certain period starting at the beginning of the trauma until sometime thereafter, which could be measured either in hours or in days, sometimes even weeks.
[Cooper:] Mark, what do you think about how he did?
[Mark Geragos, Criminal Defense Attorney:] I think it's something that you see or at least I see in the practice all the time. It was exactly what I expected. My theory has always been
[Cooper:] You said this would happen.
[Geragos:] Yes. This is exactly what you expect, that this was when we're trying to analyze her testimony, before we've heard the expert testimony, it doesn't quite make sense. Once you see it in context, now you'll understand what it is, the kind of narrative the defense is telling us.
[Toobin:] I thought this Dr. Samuels was one of the best expert witnesses I ever saw.
[Geragos:] Really.
[Toobin:] I thought he was clear. He was conversational. Now, it may be total hocus-pocus, it may be the jury doesn't buy it at all. But if the jury is looking for a reason not to give her the death penalty, Samuels did it. I thought it was extremely effective.
[Cooper:] Nark, do jurors buy so-called expert testimony? I mean, they know I assume he's being paid by the defense, he's supposed to be impartial, but they must take that into account.
[Geragos:] Well, one of the trends recently in recent years is to get experts who are appointed by the court as opposed to being a defense expert or psychiatric expert for the prosecution. Having said that, I think Jeff is right, at least so far, every account that I've seen, he seems to have come off extremely well. I think there is a tendency amongst jurors to use the expert in the following fashion. If he says something that you agree with, that kind of resonates with you, I've used that word a lot in this trial, you tend to adopt his argument and that's what you say to others or the argument you make to others when you're in the jury room and you're deliberating. In this case, I think if there's anybody there who wants to cut her some slack, that this expert combined with her testimony will certainly give them the ability to do that and argue she shouldn't be put to death.
[Toobin:] He's not saying the expert is not saying that she's legally insane. All he's saying is that she has PTSD, she doesn't her memory loss is understandable. I find that frankly very hard to believe. But I do think that as Mark said, if someone's looking for a reason to cut her a break, he certainly provided it.
[Cooper:] The idea though that she couldn't fake memory loss, I mean, do you buy it? Frankly, her explanation of the memory loss and it seems kind of shifting. I'm not sure how effective it is.
[Toobin:] That certainly is a weak point in her testimony. Mark, I'm sorry. Go ahead.
[Geragos:] Yes, I was going to say the same thing as Jeff. I've seen people feign memory loss, not just defendants. I've seen cops frequently feign memory loss whenever you catch them. So I'm not so sure that it has to be PTSD or anything else. I think sometimes people conveniently lose memory when they get cornered.
[Toobin:] The problem here is also that her memory loss is so convenient. It's always the incriminating stuff she remembers and the exculpatory I'm sorry, incriminating stuff she forgets and the exculpatory stuff she remembers.
[Geragos:] The expert had a pretty good explanation for that today, I think, and what I expected, I think, that basically that is the trauma, the things that are the most traumatic are what will produce this reaction, the psychiatric reaction that will cause somebody to lose memory.
[Toobin:] See, I don't want to get convicted syndrome. Is that what it is?
[Geragos:] Well, that's the prosecutors will call it that. The defense will say that it's trauma.
[Cooper:] But the prosecution can bring in their own expert who can say, you know, this is contrived, you can try to fake this and she's clearly trying to fake it.
[Geragos:] And that's exactly I think back to your other question, Anderson, a lot of times what will happen is the psychiatric expert by the prosecution is really good, then a lot of times you'll see jurors just say we'll cancel it out, a pox on both your houses.
[Cooper:] The prosecutor seemed really concerned that the defense was trying to get into the jurors' heads with this defense expert. Is there a line on this?
[Toobin:] Not really. That's why they call them. That's why he's there. Again, it's a subtle thing and particularly in a death penalty case. The task of the defense in a death penalty case is very different than in a guiltinnocence case. Because, you know, PTSD might not even be relevant at all if this were simply a case where life imprisonment was at stake but because her mental state and her testimony is so important on the issue of death, it really takes on a much more outsized importance. Also, just another reminder of why death penalty cases are so much more expensive than other cases because you have testimony like this that the state has to pay for.
[Cooper:] Yes. Jeff Toobin, Mark Geragos, guys, thanks very much. Up next, freefall. Take a look at this.
[Unidentified Male:] I felt that this was it. This was how I was going to die.
[Cooper:] His chute fails and he lives to tell the tale. We'll tell you how. Another Carnival cruise with yet another big stinking problem at sea.