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When was J. Paul Getty's grandson kidnapped?
In Rome on July 10, 1973, 'Ndrangheta kidnappers abducted J. Paul Getty's 16-year-old grandson, John Paul Getty III, and demanded a $17 million payment for his safe return.
What did the kidnappers of J. Paul Getty's grandson, John Paul Getty III, want from J. Paul Getty?
In Rome on July 10, 1973, 'Ndrangheta kidnappers abducted J. Paul Getty's 16-year-old grandson, John Paul Getty III, and demanded a $17 million payment for his safe return.

Question: Why was he the target?
Self-contained rewrite: Why was J. Paul Getty's grandson, John Paul Getty III, the target?