The embattled J. Paul Getty Museum is updating its art purchasing policy to require evidence that a piece has been in the United States for at least 35 years after being legally removed from its country of origin, the director said Thursday.

The update was done to keep up with British museum standards and was not a big departure from the Getty's current practices, which conform with international guidelines, museum director Michael Brand said.

"What I'm trying to do is make sure everything I do here as director is clear, transparent," said Brand, who took over the post in January.

Brand said the changes did not arise from allegations that former antiquities curator Marion True knowingly received dozens of archaeological treasures between 1986 and the late 1990s that had been stolen from private collections or dug up illicitly. True and American art dealer Robert Hecht are on trial in Rome, accused of knowingly trafficking in stolen artifacts. They deny wrongdoing.

Getty officials have also denied wrongdoing. The museum has returned three objects, including an Etruscan bronze candelabrum that Italian authorities believe was stolen from a private collection.

When buying art, the new policy requires the Getty museum to obtain evidence that the piece was in the United States by Nov. 17, 1970, when the UNESCO Convention on the Means of Prohibiting and Preventing the Illicit Import, Export, and Transfer of Ownership of Cultural Property was signed.

The policy also requires proof that the item was legally taken from its country of origin before or after that date.