A builder is facing charges of aggravated manslaughter after it was found five tonnes of rubble he had stashed on the roof of his house caused it to cave in - killing his girlfriend's four sons.
Catalino Daniel Lopez, 51, owned the house in El Jaguel, Argentina, and was said to have used the property's flat roof for storage.
Police say the roof collapsed under the weight of the rubble on January 8.
Lopez' girlfriend's four sons, four-year-old twins Benicio and Noah Nisi and their brothers Lorenzo del Rio, six, and Santino Hardoy, 10, were crushed in the cave-in.
Investigators later found that around "five tonnes of rubble" had been stored on the home's concrete slab flat roof.
This, they said, had likely caused its collapse.
Lopez is facing charges of aggravated manslaughter and, at the time of reporting, was exercising his right to remain silent.
Grieving mum Pamela Nisi - who is now receiving counselling after witnessing the tragedy - took to social media to write: "Who can take this pain away from me?"
She went on: "I can't take it anymore, why is life unfair to me? Please, I can't take it anymore. I miss you, my Lolo, my Santi, and my babies."
Pamela has two other children who are aged 15 and 18.
The eldest lives in San Justo and the youngest was in Lopez's home at the time of the cave-in.
He survived because he had noticed dust falling from the ceiling and had got up to tell his mum what was happening - then the roof of the house gave way.
Investigators told how Lopez had stored the building material directly above the boys' bedroom just hours before the cave-in.
He had been planning to make an extension to the home.
He and Pamela had known each other through work for eight years but had only started dating a few months ago.
The investigation continues.
