[Andrew Stevens:] We have breaking news from Germany. Germany investigators believe the Tunisian suspect police are now searching for in relation to the Berlin terror attack was linked to a pro-ISIS network operating in Germany. Well, the ringleader of an ISIS recruitment network was arrested back in November, police say they taught Arabic and radical Islamic beliefs to those willing to go to Syria. Now, police are in a race against time on a hunt for a Tunisian national who is believed to be connected to Monday's attack. The man is in his early 20s. They found his papers inside the cabin of this truck, one that was used as a lethal weapon plowing through a crowd Christmas market killing a dozen people and injuring almost 50 others. Well, authorities are warning that he may be armed and dangerous. The truck is thought to have been hijacked on its way from Poland, its driver found dead in the passenger seat. Well, CNN's Hala Gorani tells us where the investigation stands right now.
[Hala Gorani, Cnn Correspondent:] An urgent manhunt under way across Germany. Police warning that the driver who carried out Monday's deadly attack may be armed and dangerous, and cautioning that there could be more than one perpetrator at large. The desperate search intensifying after German authorities acknowledged Tuesday that they initially detained the wrong man, releasing the man who they picked up after forensic evidence failed to connect him to the scene. This as ISIS claims they inspired the attack, calling the driver their soldier, although investigators have yet to uncover any specific links to terrorist group.
[John Kirby, Spokesman, U.s. State Department:] We don't have enough information right now to back up the claims by ISIS that they inspired or directed or in any way involved in this. We think it's prudent for the Germans to treat this as a plausible terrorist attack.
[Gorani:] The day of the attack the Polish driver of the black semi- truck was on a planned run from Italy to Germany, delivering steel before losing contact with his employer. Authorities believe that the truck was hijacked about four hours before plowing into the Christmas market. The driver's body, shot at close range, found in the passenger seat.
[Unidentified Female:] People go here to have a good evening. To have they drink wine and eat eat something and stay here and with friends or family. And then they are dead.
[Gorani:] Thousands of mourners, including German Chancellor Angela Merkel, filing into the famous Kaiser Wilhelm Memorial Church Tuesday to pay respect to the victims. Merkel's re-election bid complicated by the assault as she faces growing concerns over her government's generous acceptance of nearly 900,000 asylum seekers over the past year. Despite the fact that initial reports about the driver being a refugee were wrong, far-right leaders in Europe are already casting blame on the German chancellor for the attack.
[Stevens:] That was that Hala Gorani reporting. We'll be speaking live with Hala in Berlin in just a few minutes. Just a few minutes ago, I spoke with CNN Terrorism analyst Paul Cruickshank and asked him why German officials are sure this time that the suspect they're looking for is, in fact, the right person.
[Paul Cruickshank, Cnn Terrorism Analyst:] They're moving heaven and earth right now to try and take him into custody, to locate him, to stop him from carrying out more attacks. We have seen this before as well, Andrew. Remember the Charlie Hebdo atttack back in January 2015, one of the attackers, Said Kouachi, also left his ID papers behind in his get away car. In that case, well, it turned out to be actually the real attacker in that case. And of course we are hearing that there was a struggle inside of the cab of the truck between the perpetrator and the truck driver. And it could have been during that struggle that these identity papers fell out. Presumably if you're going to go on the run and try and invade security services, the last thing you want to do is leave your identity papers behind. If he wanted to go that route, he could have gone a whole nine yards and left a long note to explain exactly why he did this. So, they're treating this as if it's the real deal. Of course just yesterday they released somebody that for many hours they've thought was the actual perpetrator. So, they could be very cautious in this investigation, very cautious in what they tell us in terms of definitive conclusions. But, yes, they are really interested in finding this individual very, very quickly. They believe this is a matter of saving lives at this point.
[Stevens:] Paul Cruickshank there, CNN's terrorism analyst. Well, let's go now live to Hala Gorani. She joins us from Berlin. Hala, the place not saying much officially at this stage, but we have been able to speak to contacts within the security forces tehre. What are they telling us about this the new information about the driver, the person they think may be linked to this attack?
[Gorani:] Right. Well, they're saying they believe he is connected, this suspect, to this wider network. And this is extremely significant, because it means that even though they arrested, detained and charged with terrorism offensive the leader of the network that facilitated, for instance, the transfer of fighters to ISIS controlled territory in the Middle East, that means this particular individual, if he's, indeed, connected to the attack, slipped through the net and this is something that is very dangerous for this country, because it means that an armed and dangerous man with ISIS connections and sympathies is on the loose, it's as simple as that. So, they are really racing against the clock. They've identified him as a Tunisian national, born in 1992, so a young man, 24, 25 years old. Have they were they aware of his existence before but did nothing to stop him? I mean, this could be also an embarrassment for police. So, we're waiting for more information about whether or not they had information on this particular individual, if they were ware of the existence, if they knew, for instance, that he had ISIS sympathies, and then several months later it emerges that he's connected to this attack. These are are all open questions. But this, once again, highlights the danger of some of these Islamist ISIS networks that are operating in Europe, that because ISIS itself as a group, even though that it's weakening a bit in the Middle East, is still very much a pull for some of these fighters, is able to inspire and in some ways operationally assist in the carrying out of these terrorists attacks, such as the one authorities say they believe took place on Monday, Andrew.
[Stevens:] And this particular network the Tunisian is being linked to, that was police raided them and actually arrested several members of it, right?
[Gorani:] Yeah, they did.
[Stevens:] They did, an Iraqi national, in particular, nicknamed Abu Wallad, a 32-year-old man who is makes no secret of the fact that he supports ISIS. He's been charged with terrorism offenses. There have been others, the Turkish national, people with duel nationality as well, just a collection of individuals, who authorities say are, or were, I should say, very active in promoting ISIS ideology, but also helping people travel back and forth between ISIS-controlled territory and Europe and very, very much intent on helping this terrorist group organize and carry out the attacks in this country. So, it does tell you something interesting, which is if you do detain and neutralize the leader of the network, that you have others sympathetic to the cause who maybe very closely or perhaps even more loosely connected to the group who are able to carry out these attacks. And that has to be very scary in Germany, but in other parts of Europe, Andrew, because as you know, attack happened in France, they happened in Brussels, now we're seeing one in Germany. These are countries that are all connected, it's easy to travel from one country to the another. And so what is a wonderful thing for some people, which is that this, you know, continent is open and free and a lot of people love that, well, there's that one negative aspect to it, which is it's also easy for people with very bad intentions to connect with each other. And in this particular instance, it could be the case. Although it seems as though this network, this sort of inter-regional, rather than European, you know, it still is possible for some of these fighters and individuals to travel more freely from Europe to the Middle East. So, there you have it,these are all open questions and we're waiting for more information from the police, but we hope to get that so that we're clearer on exactly who this individual is. And to your point, something like 800 Germans have traveled to the Middle East to fight for ISIS. And it's understood some probably a third of them have been able to return to Germany, so they are in Germany at the moment. Hala, I want to ask you about what has been happening today in Berlin. What developments have been going on?
[Gorani:] Well, this happened on Monday, today is Wednesday. Obviously, we're seeing some skips by appear, so it appears as though they're starting to clean up that area where the truck rammed into the market stalls and killed all these people, 12 people, including the person in the cab of this truck. So, there is an effort at cleanup, but it's still very much a somber and solemn mood. There's still these memorials and candles and flowers and people are, you know, still very sad and in a state of shock and greed. I think, though, at this point they really just want information about where the person responsible for this is or the people responsible for this are, because they really want to be able to wrap this up. It's a very tense and scary time for this country knowing that you have someone out there on the loose who might still want tod o some damage. And it is a question, as Paul Cruickshank said, of saving lives at this point.
[Stevens:] And someone now we think linked to ISIS in Germany. Hala Gorani in Berlin, thank you very much. We will be checking with Hala regularly and our other correspondents and experts as this story continues. We will be following it minute by minute. I want to move on right now, though, to another big story in Mexico. Investigators there looking for answer after a massive explosion ripped through a fireworks market on Tuesday, at least 29 people lost their lives in this conflagration. You're looking at there. Dozens more were wounded, many of them severely burned. Our Sara Sidner has more.
[Sara Sidner, Cnn Correspondent:] Mexican authorities still searching for what exactly set off this massive fireworks explosion that left dozens dead and even more injured. A horrifying sight in the town of Tultepec. Shooting flares ripping through the stadium-sized market place about 25 miles north of Mexico City. This towering gray cloud seen for miles. Images from above capture the chaos, showing emergency vehicles arriving on the scene, people running for their lives. Many of the injured escaping with severe burns, including three children.
[Unidentified Female:] To tell you the truth, I do not know how I ran out of here. Everything was so horrible.
[Sidner:] After battling the blaze for hours, firefighters on the ground confirming the fires are now contained. But the devastation left behind is staggering. Vehicles and metal charred. The marketplace bustling with holiday shoppers now reduced to rubble and ash. And this isn't the first time this pyrotechnics market has been rocked by fire. This latest catastrophe marking the third time fires ravaged this location in the last decade.
[Stevens:] Sara Sidner reporting there. And just to remind you we are following fast moving developments this hour in the hunt for a a Tunisian terror suspect in Berlin. Police are following every lead. The man they're looking for is now believed to ahve been, or to have linked the man is now believed to have been or linked to an ISIS recruitment network that is operating within Germany. The police found his papers inside the cabin of a truck that was used to plow through a crowd of shoppers on Monday evening. In all, 12 people lost their lives, about 50 were injured. The man is in the early 20s. Police say that he could be armed and dangerous. You're watching News Stream, still ahead we'll be live in Berlin again for the latest on that terror investigation. Plus, enveloped in small parts of China and choking on a pollution cloud. We have got the latest from our weather center.