A big week in the george zimmerman trial. The defense up after gripping testimony from the two moms at the heart of this case. The mothers of george zimmerman and trayvon martin both took the stand... See More
A big week in the george zimmerman trial. The defense up after gripping testimony from the two moms at the heart of this case. The mothers of george zimmerman and trayvon martin both took the stand friday and matt gutman has the story. Reporter: This morning george zimmerman's second degree murder trial is in his own lawyers' hands. His team tells abc news while the prosecution spent nine days arguing zimmerman shot martin because he wanted to, the defense will argue he shot him because he had to. My client acted in necessary self-defense. Reporter: Focusing on forensics barraging the six female jurors with images of his bloody head, his face. One of his primary concerns, the jury acquitting him on second degree murder but convicting him on lesser charges. I'm really hopeful the jury will understand that self-defense is self-defense to every crime possible and they do not look at this and say, well, maybe we'll compromise when this is not a situation where anyone should compromise. Reporter: On friday they opened their defense. Whose voice was it. My son george. Reporter: And much the same way the prosecution closed it with the mother hearing her son's voice in these howls. Who do you recognize that to be. Trayvon benjamin martin. Reporter: They called 38 witnesses, many seeming to bolster zimmerman's defense including the last witness, the medical examiner. Only one person knows. Objection, your honor, the witness is not being responsive. Nobody knows -- excuse me. Doctor, you need to wait until the question is finished being Reporter: Testimony at times chaotic and scattered. He admitted to losing evidence and changing his opinion about how long martin may have lived after being shot. For "good morning america," matt gutman, ab news, sanford, florida. More now from abc news chief legal anchor dan abrams and judge jeanine pirro with a new book out "clever fox." The prosecution finished their case. On friday and not terribly convincing. No, look, they did an okay job with tough evidence and an even tougher legal standard. The big mistake I think that the prosecution made was trying to introduce george zimmerman's various statements to police to show inconsistencies. This he's relatively minor and now george zimmerman doesn't have to take the stand because they've now shown all of george zimmerman's statements and when you have these inconsistency being relatively insignificant, if you're the defense attorney you say to yourself why would i call him? Why would I risk it? I think that's the only real tactical mistake the prosecutors made. Do you agree. I do agree with that. There is no benefit that zimmerman can gain from taking the stand. He will simply be cross-examined regarding confrontational issues in his past and there's nothing that he can say that hasn't already been put into evidence by the prosecution. The worst I thought was the interview with sean hannity where the prosecution basically humanizes zimmerman and then he comes out at the end and say it was god's will I shoot him. Are you kidding? I'm a mother. I'm sitting on this jury and i have my own son and you're telling me it was god's will that my son is going for skittles and iced tea, should be shot dead. You know, sometimes, dan, we've seen it before. Defendants just want to get up there and tell their story but a lawyer won't let him. Not in this case. You know, in some case, certainly let's say o.J. Simpson, really wanted to tell his story. In this case, george zimmerman wants to save his hide and if he does, he is going to accept mark mara's advice to him which will be very strong and very firm and very unequivocal which is you do not want to take the stand. You will not take the and and as a result, I don't think there's a real chance -- and you cannot take the stand. Yeah. The standard here, very tough for prosecutors. Well, it's beyond a reasonable doubt. Every person on that jury has to be unanimous in their belief that zimmerman was entitled not only to defend himself but the prosecution has to prove that he wasn't reasonable in his defense of himself. Zimmerman has already established that he was in fear of great bodily harm. It's evidence through all of the prosecution witnesses, clearly trayvon was on top and whatever you think of this case, the prosecution is held to an incredibly high burden of proof beyond a reasonable doubt to the satisfaction of every one of those -- to all of the charges. Yes, it's even harder in self-defense -- it's even harder in self-defense cases because you have to disprove self-defense. The prosecution. Yes, yes, and that's what makes this case so tough. Thanks very much. A lot more to come on this.
This transcript has been automatically generated and may not be 100% accurate.