Several days later, as she headed to her night shift at the garment factory where she works, Ms. Ramírez said one last goodbye to her son and his family.

When she returned in the morning, they were gone.

Ms. Ramírez remembered her son as a loyal, doting father and “a responsible, friendly, respectful son.”

Her granddaughter, Angie Valeria, Ms. Ramírez recalled, was “happy, intelligent.” As she spoke, she sat on a worn sofa covered in a sheet decorated with the images of princesses from animated Disney films. A single bare light bulb illuminated the room, a few ceramic butterflies adorned the walls.

After the bodies were discovered on Monday, Ms. Ramírez found herself scrolling through the photos of her son and granddaughter on her phone. Her daughter eventually erased them to spare her the pain.

“I would feel bad when I looked at them,” Ms. Ramírez said.

It is an agony that she hopes others will never have to suffer.

“Don’t risk the lives of your children,” she said, hoping to warn others against setting off on the potentially dangerous journey to the American border. “Those who are thinking about this, don’t do it.”

“I’d prefer to live here, in poverty, than risk my life,” she added. “But we don’t all think the same way.”