Transcript for Rescue efforts continue after devastating earthquake in Mexico City

To Mexico City at this hour. Days after that earthquake and the cheers erupting at a factory that came down during the earthqua earthquake. Matt Gutman with the moment that another person was found alive. Reporter: Tonight amidst the flattened buildings there are spikes of hope. Cheers erupting at this flattened factory where another person was found alive. Those rescues dangerous as we saw firsthand. Debris crashing down around us. Watch it watch it! Moments later officials clearing the scene fearing another collapse. We joined the search and rescue team at this pancaked office building gearing up for a grim search. Fire rescue teams say that those six stories collapses so densely that there's no void space and concern is nobody could have survived. And under these tarps the families of the dozen or so missing prayed. It was after those prayers that we met Fabiola. Her brother is in that building. She showed us around the improvised tent where families had been living for the past four days. They're all there. Cousins, sibling, friends. And then that call for silence. Shh. Reporter: Now they call for silence because that's when they try to listen to something in the rubble. These are the moments of hope. She told us they need to show strength. But after four days even iron will can snap. Ch she says her brother is very strong. ??? Reporter: Everywhere solidarity for Mexico. ??? Reporter: On the rubble of this building a salute to the Mexican national anthem. And Matt from Mexico City. The scene of that apartment building and Matt you're hearing they're bringing in a crane to lift up sections of the building? Reporter: That's right David. The crane is going to lift layers of that building where you see that swarm of rescuers. Which is a sign that this could turn from a rescue operation to a recovery operation. For days we have been asking Mexican officials for the list of the missing but in the scope of this devastation they say they still don't have one. David. Matt Gutman on the scene. The major headline, a major blow in the new effort to kill

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