Mexico's office of the presidency says the death toll from a magnitude 7.1 quake has risen to 273, including 137 in the capital.
Family members of the dead travelled overnight from other states to attend Wednesday's wake in Puebla.
The death toll in the powerful 7.1 magnitude natural disaster that rattled Mexico on Tuesday climbed to 250 as rescue workers backed by an army of volunteers on Thursday searched for survivors buried under mounds of rubble, officials said.
Assistant navy secretary Angel Enrique Sarmiento said there was evidence of a person who may still be alive, but it was probably a school worker.
The report appeared to put an end to a national fixation on the search for a child - dubbed "Frida Sofia", though there was no evidence of an actual child by that name - who was said to be missing and possibly alive in the wreckage of the school.
A couple of hours before Tuesday's quake, authorities held a city-wide drill in the anniversary of an quake that killed an estimated 9,500 people in and around Mexico City in 1985, one the country's worst natural disasters in recent memory.
In all this, Alvarez-Woo says she finds hope in many stories of people coming together in a hard situation.
Guadalupe Salinas-Riojas says her 26-year-old son is still inside.
"Unfortunately many people have lost their lives, including girls and boys in schools, buildings and houses". She had no way of reaching her friend who was supposed to pick her up at the airport.
She says, "My son has been buried for hours, no one will tell me a thing". In her words, "I think what kills us most is the desperation of not knowing anything".
"He was still inside the school, and he was dead when they rescued him", his aunt Paola Rodriguez told CNN.
The remains of the building had shifted dangerously earlier Thursday morning, prompting some rescuers to evacuate the top of the pile.
Workers have put into place iron beams to prop up the structure.
Stretchers have also been brought to the edge of the building. "This is an indication that the state - the people together with the government - will cope with these challenges of nature", the statement says.
The rescue dog is being hailed a hero on social media.
The team's arrival coincides with a sad anniversary; experts from the same division were also dispatched to Mexico after the deadly 1985 quake that killed thousands.
"We are in a quiet period right now, they have been working through the night at this school they believe they are getting close to the 12 year old girl right now".
"The first five seconds felt like it was about an hour long, trying to actually figure out: 'Is this really happening?'" Kishiuchi said in a video conferencing interview from Mexico City.