turning down a bailout and turning his business around. plus, only in america, strurk by lightning after buying his mega millions ticket. if it wasn't for bad luck, he would have no luck at all. this is "piers morgan tonight." good evening. our big story, the death of trayvon martin. unanswered questions are piling up in this case. two audio experts say the screams on a 911 call do not seem to be the voice of george zimmerman. the surveillance video on zimmerman at the sanford police department which an outside company for abc news seemed to show some kind of marks on the back of zimmerman's head. much more on that in a moment. just hours from now, republicans turned their epic battle to wisconsin, maryland and d.c. for tomorrow's vote. it will be the turning point of the race and how many candidates will be left standing? we'll hear from rick santorum very soon. first, our big story tonight. trayvon martin. what really happened the night he died? joining me, forensic experts patricia cornwell. and criminal defense attorney, allen derschwitz. you've hinted if you were defending george zimmerman, you reckon you would have a pretty good chance at getting him off. >> unfortunately, florida has this absurd stand your ground law which makes it very, very difficult to successfully prosecute people who may have deliberately and willfully shot. all they have to do is raise a plausible claim of self-defense and all kinds of restrictions kick in. remember, there are two versions of what happened here and they're both rather extreme. the martin version, the martin family version is that zimmerman was following him. there was no provocation. he started the fight and then he shot him in cold blood. that would be very simple first-degree murder. the zimmerman account is equally simple minded. that is, the young man trayvon martin hit him from behind. jumped on top of him. grabbed for his gun sxmd you're going to die tonight. if that's the case, it is a simple case of self-defense. when the forensics come out finally, when the autopsy comes out, we'll find it is a much more nuanced case. it will be on who hit the first blow. since there are no real witnesses, there may be reasonable doubt under florida law. >> patricia, forensics, forensics, forensics. never have i seen a case in recent times that could in the end have forensics be more important than this. >> that's exactly right. and he is exactly right. what we're waiting for is what did the medical examiner really find? what is the trajectory of the bullet? was it a contact wound? a slightly distant wound? is the location of the wound consistent with the handness of the shooter and what he says about where he was positioned at the time of the shooting? such as if he says he was on his back or they were standing up or who knows what? in addition, the gun. does it have trayvon's dna on it? does it have his fingerprints on it, on it or the holster that might indicate anything. what is on the iced tea bottle. maybe there was some sort of struggle. the alleged wound to the back of the head. how do we know that wasn't caused by maybe somebody who was frighten asked hit somebody with their phone because that's all they have in their has not or a bottle. those should be checked for dna and evidence. the clothing should be chegd for trace evidence. >> when you saw the fbi, pictures of them crawling all over the crime scene, is this good or is it too late for this case? >> well, you know, i would like to think it is never too late themselves may get something just from the location. but there can't be anything left there now. this was back in february and it was raining that night, too, which makes it difficult. you know what happens, piers, when these kinds of terrible things occur, the police don't know how big it will be. they didn't realize the whole world would be watching this case when they went out there. >> how significant is this? let's have a look at this. this was a video that did the rounds a few days ago. we all jumped on this and said, well, look, the guy is barely showing any signs of injury. he must be inventing his story. when you look at the enhanced video which abc had done, you can apparently see, we have to use these qualifying phrases. red marks all over zimmerman's top of his head. if that is genuine and they were inflicted by trayvon martin, how does that change the case you? don't know still. was that a defensive attack because someone else, trayvon had been hit first? we don't know. by the way, i hope they photographed those injuries. the medical expert needs to look at those to say, how do you know they're not self-inflicted? how do you know that somebody didn't want to make it look like they were attacked because they're waiting for the police and there's a dead body on the ground. >> you're down there on the ground in florida. the mood has been raging now for quite a while. people on both sides jumping on every new piece of information that the media releases. we can see from the debate over this video. one minute it looks like it is very beneficial to the trayvon martin supporters' case. on the other side, today, you may argue it is actually helpful to george zimmerman and his case. what is the mood now right now? is it dangerous that the media keep putting this stuff out there and basically convicting or acquitting based on every new twist and turn? >> well, what i think is dangerous is that people take the facts that reporters are digging up and they're making suppositions. they're assuming what happened. they're trying to draw inferences. putting out the video was a journalistic enterprise. it became public domain. they provided it so people could look. when commentators looked at the video and said i don't see any wounds, the video was blurry. he might have had wounds. and we did hear that he got some kind of medical attention in the back of a police car before he was taken to the police department. so blood may have been cleaned up. and cuts may have been attended. to i think the problem is that there is a huge amount of emotion. you've talked about this. we've had protests here in the tampa bay area in south florida, in sanford. they're still going on. people are still, checking money for the family. and i think people are really concerned about figuring out how effectively did the police go after this. was there some breakdown? some small town justice going on here? those are the questions people want. i think if we have factual reporting, people concentrating on trying to find out the facts of the case, we'll be much better off. >> alan, my view from the start of this has been a kind of incredulity. that george zimmerman wasn't arrested that night. i mean if this had happened in britain, he would have been arrested right then and there and then face ad normal criminal legal process. and clearly, the authorities on the ground were split here as to whether he should have been or not. to let the guy just go home in the clothes he was wearing, with no apparent legal process even being commenced. it is that that seem to have really angered people. what do you think of this from a legal point of view? >> well, i think there's a big difference between arch is a formal legal proceeding for which you need probable cause under the statute. the statute makes arrest very difficult to achieve. but also, the other factor, they could have done much more forensically. they could have taken dna from under his nails. they could have taken his clothing away from him. they could have taken and programs they did, close-up photographs. i won a case a few years ago as a result of a photograph taken at a crime scene which purported to show a kind of killing, and then we were able to demonstrate if you blew up the photograph, it showed something very, very different. the kinds of real-time forensic evidence that can be obtained only within minutes or hours after the crime is absolutely essential. if the police failed to do that, they really did fail to provide evidence that could give us the truth in this case. the arrest is a very different matter. because arrest is a legal proceeding that is required to pass muster under certain criteria, under the statute. this statute is a horrible statute. when you combine florida's penchant for guns. a couple years ago they tried to make it illegal even for a doctor to discuss gun ownership with his parents. everybody seems to have guns and then you have your stand your ground. you combine that together, it is a prescription for disaster. of course, for defense attorneys like me, it is wonderful because you win cases that you shouldn't win as a result of this statute. >> and it's important to note, that's exactly what has been happening. more and more people are now getting off in these kinds of situations by using stand your ground. >> the interesting thing is most defense attorneys i know are against the stand your ground law. this is one thing where prosecutors, defense attorneys, police, everybody agrees, this is a horrible statute except the national rifle association. >> can i break in for a moment? >> i'm just going to may a clip here and i'll come to you after this. this is a clip we put together. it includes the screaming audio which i think has become very significant. >> do you need police, fire or medical? >> maybe both. i'm not sure. there is someone screaming outside. >> who was screaming there, robert? >> that's my brother. >> people can say anything they want to. i just personally don't believe i i know it was my son crying out for help. >> airing, let me come to you. you wanted to jump in there. what did you want to say? >> one thing i wanted to point out. i'm no legal scholar but zimmerman's defense has always been self-defense. i think one of the issues we face here, is that stand your ground may not even apply. he claims he was attacked and he was defending himself. i think this would be a tough case even if we didn't have a stand your ground law. >> let's talk about this audio issue. we got both sides claiming it is on george's side, that it is him on. trayvon's side, that it is him. very significantly, i think, there is now been this independent study done for the orlando sentinel which seem to conclusively prove or certainly suggests very firmly, it is not the voice of george zimmerman, compared to the other audio of him. they haven't got audio on trayvon martin so they haven't been able to say it is definitely trayvon martin. but the law of deduction says if it is not george zimmerman, it is probably trayvon martin. >> i think the voice print comparison is really, really interesting. a very old technology, believe it or not. it has been around since the 1940s. what i would hike to see done, i would like the same analysis done with trayvon's voice. i can't help but think someone will say, what if you got the same results when you analyzed his? plus, you have the difficulty of you're analyzing high pitch screaming. and i don't know what the exemplars they compared it with but it is probably somebody speaking. i think it would be tough in court. but i do think that forensic technology is viable as a great investigative tool. >> it seem on the forensic side, the local police have been incredibly lax. >> i hate to judge police. i think they don't realize this is a case that will be all around the world and they're working it, maybe it wasn't a high priority. >> the question i've asked quite a few guests in the last few days frg it had been a white teenage boy who had been killed by a black man, i'm pretty certain there would have been an arrest. isn't that a fact that is causing a lot of the anger here? that it seems to have been just as skewed against a young teenage boy? >> that is the question bothering everyone. of course there's anger in that. i would caution against -- the thing bother manager is people are making so many assumptions. we don't know what would have happened if the race was reversed? they still would have had a young kid dressed in the street manner. neighbor police would have reacted the same way. they know of george zimmerman and they knew he had been helping as a neighborhood watch person. what i want to see, tv is great at channeling emotion. we've seen a lot of shows including yours channel people's emotion. at first there was a lot of sympathy for the family. we were doing stories because they were speaking up and the local cops didn't seem to be doing their job. when the 911 tapes came out, even more sympathy. as zimmerman began to speak out, surrogates for zimmerman, his family, his attorneys, that began to waiver. and i think we have to be very careful to focus on the facts and on what happened. making suppositions about whether someone is injured or not, this 911 analysis, i'm very skeptical of it. i want to know facts. i would tell people, look at the orlando sentinel and the "miami herald" and our own paper. the newspapers have focused on facts. let's try to tone down on the emotion a little bit and focus on what we can find out. >> i wholeheartedly endorse everything you're saying. a last word? >> well, i think there is a big difference between facts and admissible facts. take, for example, the expert voice analysis. that's dramatic and terrific newspaper stuff. not clear that that would be admissible in a trial because it has to pass a certain threshold of scientific credibility. so we may end up with a situation where we know facts, but the jury who ultimately hears case, if there is an arrest and prosecution, won't know those facts and you would get a disparity outcome. based on what the jury heard, there might be an acquittal. so nobody knows how this case will end up. it is much too nuances, we shouldn't accept the two extreme views until we've seen the forensic evidence. >> thank you all very much indeed. coming up, rick santorum and what could be the tipping point in his epic race. 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what if i will you he supported radical environmental job killing cap and trade and the wall street bailouts? and what if i will you he dramatically raised taxes and stuck taxpayers with the $1 billion shortfall? one more thing. what if i told you the man i'm about isn't him. it's him. >> that's the latest attack ad from rick santorum's campaign unleashed on mitt romney's positions. identical to president obama's and the candidate himself rick santorum joins me now. how are you? >> i'm good. i'm pleased to be here in ripping wisconsin. and actually at the home of the republican party and the little school house where the first meeting was. >> we're going to come to the republican race in a moment. i want to ask you first of all about the trayvon martin case which is showing no siphon losing any steam. a huge national debate going on about this. do you believe all things considered, all the information we now have, that it would be the correct thing to do for george z zimmerman to do, to be arrested? >> i'm not going to weigh into this case. you say all the information we know. it seem like information keep coming out and conflicting information. i'm running for president of the united states. what we have to do is trust the criminal justice system. make sure that there is adequate oversight from the state level to make sure this case is being handled properly. and i'll let the local and state law enforcement agencies to figure this out. >> what about this stand your ground law? there is been so much attention based on this law. it does seem that it has been used by a lot of the wrong kinds of people now to avoid justice. would you accept that? >> well, the stand your ground law is to allow people to be able to protect themselves. and make sure that they have the right to self-defense. the idea that the stand your ground law means you can do anything but that is simply, well, simply that's not what the hau is there to do. and i think the law has limited application. and i think in its application, it is proper. >> there's been another horrific incident today. a shooting at a university in oakland. at least seven people were killed. it raises the whole issue of gun laws in america. i'm aware that candidates run a mile on this debate. given the sheer number of cases of people getting access to firearms who simply shouldn't have them, who then go on to commit these crimes, is it time for a big review of gun law in america? >> no, it's not. i don't run from this debate at all. i run toward this debate. i believe that the right to bear arms is an essential right for our country. and people being able to enjoy the shooting sports, as well as to use guns to protect themselves from incidents like this. the bottom line is what you're talk b is someone who had a firearm and used it for an illegal purpose. we don't know how they got it. the issue is not the availability of guns. the issue is the individual with regard to the use of that gun. it is not a firearms issue. it's a human issue. obviously a very sick and troubled person. but the idea that the gun is the issue here is simply off base. it is the person doing the act is the issue. >> let's turn to the gop race. obviously, a big night for you tomorrow night. you are facing potentially according to the polls, a triple whammy here. if you were to lose all three and mitt romney won all three, would you not be tempted to say, okay. that's it. i've had a great run. he is clearly going to be the nominee. >> i get that question more than how are you today? look, when we finished up with the great one in louisiana at the end of march, won by 23 points. we had a great march. we won at love states in march and exceeded every expectations. we've done a great job in taking the seven loaves and fishes and turning it into 11 state wins. it's been a great opportunity. yet we knew that april would be a very tough month for us. this is a sires of s