French Polynesia is a non-extradition country.
Most of Tetiaroa is private property. from wiki: “In 1904, the royal family gave Teti’aroa to Johnston Walter Williams, the only dentist in Tahiti...Brando eventually purchased Teti’aroa’s islets (motus) from one of Williams’ direct descendants, Mrs Duran. The reef and lagoon belong to French Polynesia.”
Ping to nip’s question on whether there’s extradition treaty with “brando’s island”:
http://www.freerepublic.com/focus/news/3538916/posts?page=53#53
And blueplum’s answer; no extradition treaty with that nation:
http://www.freerepublic.com/focus/news/3538916/posts?page=75#75
IMHO the length of time he stays abroad, reflects what’s happening behind the scenes in regards to his crimes & their investigation.