JERUSALEM — An Israeli man has been detained in Europe on suspicion of plotting to kidnap the granddaughter of the late shipping magnate Aristotle Onassis.

The arrest last week in Milan came just days after the Israeli police dropped their investigation into an alleged plot to kidnap Athena Roussel, the 12-year-old heiress to the Onassis fortune.

But Swiss officials still believe that at least six Israelis conspired to kidnap her while she was vacationing with her father in St. Moritz, Switzerland, earlier this year.

Israeli police officials told Israel Radio last week that several Israeli suspects had disclosed during questioning that the pursuit of Athena Roussel was ordered by her father's rivals in order to make him lose custody of her — and that there was never any intent to kidnap her.

Athena Roussel, who is the daughter of the late Christina Onassis, is expected to inherit $2.4 billion when she turns 18.

Her father has filed a lawsuit to take control of her trust fund.