The death toll from devastating landslides in southwest Colombia has now climbed to 301, including nearly 100 children, authorities said, as a grim search to find hundreds of people still missing continues.

Surging rivers triggered by torrential rains on Saturday sent an avalanche of floodwaters, mud and debris through the southwestern city of Mocoa, causing widespread destruction.

There were 92 children among the 301 people killed, Colombia's Disasters Risk Management office said on Thursday.

Officials late on Wednesday announced a probe to determine whether town authorities had correctly enforced building regulations and planned adequately for natural disasters.

Edgardo Maya, the national comptroller, said the investigation was "not about punishment; it's about prevention."

"What good does it do to punish people now, after so many deaths?"



Mayor Jose Antonio Castro, regional governor Sorrel Aroca and their predecessors face a separate investigation by prosecutors, according to Colombian media reports.

READ MORE: Bodies decomposing in Mocoa morgue after landslides

Meanwhile, survivors like Joanis Marvel continue to wait at Mocoa's morgue where bodies - often too decomposed to be identified except through DNA - continue to arrive.

Marvel's mother, brother, nephew, sister-in-law, grandmother and daughter are yet to be found.

They are among the 314 still missing, a figure provided by President Juan Manuel Santos in a national speech on Wednesday.

"I just need to find her, even if it is in a box," Marvel said of her daughter, speaking to Al Jazeera.

Members of the civil defence, firefighters from neighbouring towns and other volunteers often know where to start looking because they are guided by a stench.

"It's been smelling really bad here since yesterday. There has to be a body," a relative searching for 46-year-old Luis Eduardo Zuniga, along with 10 other family members, told the AFP news agency.

Digging in the mud with sticks and bare hands, they excavated the area around a semi-collapsed house, until it was deemed too unsafe to continue.

"We'll have to get heavy machinery in here," a volunteer told AFP.

But many still do not have the right equipment to free bodies, despite President Santos' call to release funds for rescue and reconstruction.

"You can see for yourself that our neighbours are underneath those knots of wood and my chainsaw is not enough," said Gustavo Villareal, a volunteer holding a chainsaw unable to cut under water, told Al Jazeera.

He and 12 others worked nearly three hours to free the remains of a man from underneath a trunk.

"I am angry that not even in this situation do we get the resources that we need," he said.

WATCH: What caused Colombia's deadly downpours?

As the work to find the missing continues, police have also set up checkpoints in Mocoa to question those carrying household goods.

Authorities say they have already arrested more than 20 people accused of looting abandoned houses and shops.

While some 2,700 residents are now being housed in shelters, others camp out where their homes used to stand to defend what belongings they have left.

"The day after the landslide we managed to get some things out of the house. But when we came back that afternoon, they had taken it all," Juan Luis Hernandez, in the destroyed neighbourhood of San Miguel, told AFP.



"What the mudslides didn't carry away, the thieves did."