Rescuers searched frantically for Maria Ortiz, a cleaner believed to be trapped under the rubble. Using the information to pinpoint their location, rescuers freed her and the three other survivors.

'Those messages helped them know more or less where we were located,' Ms Pacheco said from her hospital bed, her voice weak. Ms Pacheco, a recruiter for a human resources and accounting firm, said she sent the messages shortly after the magnitude earthquake struck at 1:14pm on Tuesday. When asked whether WhatsApp messages can be delivered hours after they were sent in an area without good phone coverage, a spokeswoman for the company confirmed it was possible. Quake in videos and photosĮyewitness video and photo shows the moment the powerful quake struck, and its aftermath. The messages on Mr Garcia's phone, seen by Reuters shortly after they were received could have been delayed due to erratic mobile phone coverage in parts of Mexico City after the quake, or the fact that Ms Pacheco's phone signal was blocked by the tons of concrete that kept her trapped in the collapsed building.

'It was like a miracle because I was the only one who got the message and since I was there with the rescue workers I talked to them and they could locate her,' Mr Garcia said. Juan Jesus Garcia waited in tears beside the collapsed building all night for his wife Diana.

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