According to AARP, this is a common scam that has cost grandparents millions of dollars. Unfortunately, the tax rules don’t help in any way. The deduction for a theft loss—assuming such scam is a theft under state law—cannot be claimed in 2018 through 2025.
A capital loss that is not deductible because it exceeds the annual $3,000 capital loss ceiling. A carryover loss may be deducted from capital gains of later years plus up to $3,000 of ordinary income.