[evilduck]

I'm no tax lawyer but it would seem like a kidnapper wouldn't meet the criteria for having legal custody of a person and wouldn't qualify for any relief of their tax burden. But given that a large number of those type of kidnappers are family members, it's likely they already have the information needed to file them as a dependent (which in the case of a kidnapping, seems like it would be cut and dried tax fraud).

The question that lingers in my mind is if your dependent is kidnapped and gone for too long (but not dead... let's say they're kidnapped on December 31st and returned 366 days later conveniently removing custody for an entire calendar year), are you ineligible to claim them as a dependent while they're missing? Seems like strictly and amorally speaking your financial burde has been lessened and you wouldn't need the tax relief for caring for that person.