My son told me he’d sold his soul to the devil before shooting his sister, 15, I lost both kids in one day

Returning home from work, Sonia Ramirez instinctively knew something was wrong. As ever, her mind turned to her 19-year-old son, Ignacio, who had been an increasingly scary presence in the house. His sleepless nights, pacing around downstairs, getting into trouble with the police and an attack on her, had culminated in the chilling comment from...