The 72-year-old is the victim of a cryptocurrency scam involving the popular platform Coinbase. Over the years, she had saved $36,000 in her account. But one phone call last month changed everything.

Sixteen-year-old Darkuna watched, terrified, as six gun-wielding men ransacked her home. “For God’s sake, what do you really want?” she cried. One of the fighters looked directly at the girl and ...