Isis attack. Terrorist behead two activists who work to expose isis brutality. The brutal murders happening in their own apartment in turkey far from isis territory. Is isis strengthening its network of terror . Trying to fix. Jeb bush attempting to retool with a new slogan and bus tour. But his numbers in a key early voting state are stagnant in a brand new poll while rival marco rubio is surging. Will the reboot give bush the boost he needs . Im wolf blitzer, youre in the situation room. Were following the investigation into the crash of that jet liner in egypts sinai peninsula. Remarks by an airline official are only deepening the mystery. Hes blaming, quote, a certain impact for breaking the airbus a320 apart in midair. Islamic militants affiliated with isis are claiming responsibility which killed 224 people. Officials in both russia and the u. S. Are downplaying that questioning whether the group has the ability to down a jet at High Altitude. But they also arent ruling out a missile or bomb as a possible cause of the crash with russias air transport agency saying its too soon to speculate. The planes black boxes have been recovered and are awaiting analysis. At least 175 bodies have also been recovered from the crash site. Most of them in tact according to a source. Recovering all of that and much more this hour with our correspondents and our expert analysts and our guests. Lets begin with the crash investigation. Cnns brian todd is working the story for us. Brian, no one at least right now is ruling out terrorism, i take it at this point. Even americas top intelligence official is not ruling out terrorism. Investigators are facing a daunting challenge tonight. Theres a menacing terror Group Operating in the sinai which wants to bring down planes and but experts are also telling us there are mechanical and faulty repair issues which could cause a passenger plane to break up at that altitude. In the air for 23 minutes flying at cruising altitude flight 9268 was at a point where planes rarely break apart. The vast majority of airliner accidents occur on takeoff and landing. And cruise flight is really the safest portion typically. Reporter but tonight 224 people are dead. The planes wreckage is scattered across eight square miles of the sinai desert, and serious questions are being asked. What about the claim from isis that its responsible . We dont have any direct evidence of any terrorist involvement yet. Its unlikely, but i wouldnt rule it out. Analysts say the isis affiliate in sinai has the intent to attack commercial aircraft. Theyve stockpiled shoulderfired surfacetoair missiles as seen in these training videos. But experts say those missiles cant reach that high. Were talking maximum between 10,000 and 15,000 feet. Maybe if you stretch on a really good hail mary maybe 20,000 feet. But 30,000 feet is not practical. This military analyst says the russian made buk Missile System which brought down the malaysias plane last year. But requires more manpower and training than that isis affiliate likely has. You have a control vehicle and another vehicle which controls extra missiles. Wub theory investigators will likely pursue, did a terrorist sneak a bomb onboard . Airline Safety Experts say there are ways other than terrorism that a passenger plane can break up at altitude. Improper maintenance including a failure to detect and correct corrosion or an improperly done repair, or weve had oneoff events fuel tank explosions, cargo door failures, things like that. There are horrific examples. Crash of twa flight 800 in 1996 believed initially to be terrorism was later determined to have been an explosion of flammable vapors in a fuel tank. Japan Airlines Flight 123, the 1985 crash considered the single deadliest accident in aviation history, more than 500 killed. It was determined that a previous tail strike had damaged the planes rear pressure bulkhead and the repair was faul faulty. A similar thing happened to this russian aircraft. In 2001 this planes tail struck a runway while landing. It was repaired and an official of the airline says the plane had been checked thoroughly for cracks. But Safety Experts are telling us tonight it is possible that a defect in the repair was simply not visible and a crack could have spread very rapidly during the time this plane might have been dissdisintegrating, wolf. What about the possibility terrorists could have fired from the plane from some of those mountains in the sinai region . Those mountains are pretty high. Youve been checking into that. We have, wolf. Theres no definitive answer to that tonight. Military analysts say the mountains here in the Southern Region of the sinai could potentially give a boost to someone launch ago shoulder fired missile. Those mountains extend up to about 8,000 feet above sea level. But experts say its still likely not enough height to strike a plane at that altitude. Plus, wolf, these mountains are about 100 miles away from where the plane came down. Its probably too far to fire a shoulder fired missile and hit it from that distance. Again, the height not quite high enough. Again, theyre examining all these possibilities tonight, wolf. Brian todd, thanks very much. Vague statements by russian officials early adding to the mystery of this airline disaster. Our Senior International correspondent Matthew Chance is in st. Petersburg, russia, right now for us. Matthew, an Airline Executive seemed to suggest an impact of some sort on the plane, an external impact may have caused this plane to go down whachlt are you learning . Reporter yeah. Well, its very difficult, isnt it . Because he was using deliberately vague terminology to sort of explain that he didnt believe it was a Maintenance Issue or a pilot error issue. In other words not a company issue. That could have been responsible for death of these 224 people. Trying to shift the emphasis to this theory that it was something external that caused the catastrophe being marked not just here in st. Petersburg but all across russia as well. But the trouble is is that those vague statements as you call them are intention with perhaps what the kremlin is trying to push this idea that it wasnt terrorism that it could have been some maintenance problem. It could have been some technical failing that led to this. Either way, its not looking particularly good for the kremlin because they either depending on which way the investigation goes and it really is up to the investigators now to try and answer some of these questions, if its a technical error the government will be accused of not doing enough to protect its passengers on these Civil Aviation flights. If its terrorism, in some ways its even worse because then the government is open to the accusation that this is blowback, this is retaliation for their policy in syria where theyve been carrying out air strikes for the past several weeks, wolf. Matthew chance, well stay in close touch with you. Thanks very much. I want to bring in our Senior International correspondent arwa damon. Shes joining us from cairo. Arwa, egyptian investigators theyre also working this crash investigation. What are they saying . Reporter well, wolf, you have egyptian and russian investigators on site as well as a team from airbus. Now, this is what were being told from a number of different sources. At this stage according to an Egyptian Military source none of the militant groups that operate in the sinai actually have the Necessary Technology to bring down a plane at 31,000 feet, at best, according to this source. The shoulder fire surfacetoair missiles that they have could hit an aircraft at about 15,000 or 16,000 feet. According to one of the russian state agencies they reported quoting a russian source of theirs on the ground whos part of this investigation as saying that initially the debris, the remnants that they have been testing for explosives have not tested positive. Bearing in mind this is initial and the debris is spread out over an expanse of eight square miles. We also spoke to a medical source who had seen around 175 of the bodies. Hes been helping out with processing and recovering them. He said that about 60 to 70 of the bodies were in tact. And none of them had significant burn marks. Of course everyone is hoping that those two black boxes that were recovered fairly quickly on saturday the same day as the crash took place will be holding some of these answers. We dont know at this stage though exactly when that vital data is going to be recovered, wolf. All right, arwa, thanks very much. I want to dig deeper on all of this. Joining us the former ntsb managing director our cnn aviation analyst peter goelz, our Law Enforcement analyst tom fuent fuentes, our aviation consultant former pilot alister and richard quest. Richard, youve been doing a lot of reporting on whats going on. What is the leading theory at least at this point on the investigation . There isnt one, wolf. I mean, we can pretty much start to discount missile. I havent heard one security expert suggest a missile could have reached at all or that isis has those missiles. But now youre talking about some form of inflight breakup. And whether that comes from an onboard explosive, a bomb for a better word, or a breakup because of a previous bad repair, or other reason, there is no favored theory at the moment. And frankly those who, you know, say with great certainty it had to be this, that or the other, really are not necessarily being fully frank. Tom fuentes, how soon will we be able to rule out if there was in fact a bomb inside the plane . Remember pan am 103 there was a bomb inside that plane. How soon will they know if there was a bomb . Well, i think, wolf, it could be a long time. And one of the problems is if youll remember the twa800 when that plane crashed it was about three years before they determined that it wasnt terrorism, that it was a Center Fuel Tank and vapors in it with an electric spark that exploded. It could take a long time to determine that. But the bigger problem here from my perspective is that both sides, the russians and the egyptians, are not going to be completely reliable. For the russians sake theyre not going to admit that they had a horrible maintenance record with that aircraft. And from the egyptians side theyre never going to want to admit that it was a terrorist act because Sharm El Sheikh is one of their leading tourist destinations. And they dont want people to be afraid to fly there. Were told, tom, isis at least the terrorists who were operating in sinai dont have the capability of shooting down a plane thats flying at 30,000 feet with a shoulder fired missile. But how can they be certain that they dont have other more sophisticated surfacetoair missiles that could shoot down a plane flying at that altitude . I dont think they can be certain of it. You know, as richard said, these are all theories. None of these have been proven yet. Even a good indication yet of what may have happened. So it is premature to say, but again, you know, were going to have to question the investigation until we have a good reason to accept that it is credible. Peter, what else could cause a plane to break apart like this in midair at 30,000 or 33,000 feet . Well, wolf, theres a variety of things that could have occurred. One is that the repairs done after the tail strike might have been done inexpertly or had not been monitored correctly over the intervening years and fatigue cracks had grown and it simply let go as it reached altitude. Another could have been a cargo door or a rear passenger door that had not been latched securely that that let go. Or it could have been something in the cargo hold of the plane. You know, theres a great deal of speculation about lithium batteries these days. Well want to get a look at exactly what was put in the cargo hole and whether there are any bad actors there. So the key though, wolf, is to go back along the flight path of the plane and get the debris that came off first. That will tell you where it started and might give you the solution. I assume theyre doing that. Heres the question a lot of people are asking the egyptians and the russians theyre the lead investigators right now. Can they be trusted to get to the truth . Well, i have to say i share toms skepticism. Ive worked with both russian the russian investigators and with the egyptians after egypt air. They allow politics, National Political interests to get in the way of safety investigations. So i share toms skepticism. As far as you know have they invited the ntsb or the fbi or any americans for that matter to come in and help in the investigation . They have not. Even though these were u. S. Engines that were on this plane, the ntsb has not sent any investigators. And they might in part because this is a war zone. And the investigators really would prefer not to function in but the french are there and the germans. And they have a good Investigative Team if they follow the iko standards. Allister, were told the flight data recorder is apparently in good condition. How useful will that be in this investigation . Well, it will be vital. It will show whether or not all systems were running normally or whether they were faulty. It will also show the altitude of the aircraft, its speed. There are a number of parameters all of which will show an abnormal or normal situation. If its a perfectly normal situation up until the point at which the aircraft started to descend rapidly, then it would suggest that something sudden had happened. You know, i think its going to be very difficult to hide the facts of this having the flight data recorder and the cockpit voice recorder. Those two pieces along with the wreckage which is all going to be recovered, i dont think theyll be any, you know, thought this might be covered up. Im sure well find out in due course what caused this accident. Lets hope. All right. I want all of you to standby because were getting more information thats coming into the situation room right now. Stay with us. 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Were back with the experts discussing the crash of the Russian Airliner in egypt that killed all 224 people onboard. One airline official blames what he calls a certain impact for breaking the plane apart in midair. Peter goelz, i want to show you some pictures, some photos comparing the debris field in the mh17 commercial airliner that was downed over ukraine not that long ago, last year. Take a look. Thats on the left part of the screen. On the right part of the screen you see the wreckage from this particular crash in sinai. It looks very similar both of that. What if anything can we make of the similarity of these two images . Well, i think it indicates, wolf, that there was a separation at altitude in both cases. Something catastrophic happened to this airline at altitude. We know in mh17 it was hit by a missile and came apart. In this accident or incident we dont know yet what happened. Richard, back in 2001 this plane, this airbus commercial airliner struck the runway during landing. The tail was damaged. There have been two instances in aviation history where planes broke apart midair years after they had incured damage to this area of the plane, potentially could that have happened this time . Yes, it could. And if it did its nothing short of a disgrace since the incident youre talking about particularly the ci one are very well known. Look, the repair the plane at that time was being operated by mea, so metrojet and its predecessor had nothing to do with it. It was many, many years before they took over the aircraft it was owned by a leasing company. But everybody who touched, owned or operated that aircraft will have known about that tail strike. And therefore firstly should have always as been ensuring that that repair remained good. Metal fatigue is another issue. It shouldnt be a problem with a plane of only 18 years old, but what youre coming to here, wolf, is maintenance. Was this plane being assuming we can put aside nefarious, was this plane being properly maintained . And the fact, richard, that there was no distress call from the cockpit, no mayday, mayday, mayday, apparently none of those indications. What does that say . Well, some people will say it Means Nothing because, you know, theyre too busy flying the plane to get a mayday out. I dont necessarily buy it in this particular case. I think it is significant. And i think its significant because of not on its own but if you look at the trajectory of the aircraft, wolf, this thing fell out the sky. And its speed just disappeared. It went almost like it had hit a wall. And if you put that togeth