PITTSBURGH — A museum director says she's confident that cadavers in an exhibit in the city were procured legally, although a doctor involved in preserving such bodies says he destroyed others due to fears that they were executed prisoners.

"Bodies ... The Exhibition" has drawn about 150,000 visitors since it opened at the Carnegie Science Center in Pittsburgh in October.

On ABC's "20/20" program Friday, Dr. Gunther von Hagens said he had to destroy some bodies he had received from China because they had injuries that made him suspect they had been executed.

He invented a liquid plastic process that preserves bodies, some of which are part of the Pittsburgh exhibit.

Carnegie Science Center director Jo Haas issued a statement saying she's confident that the bodies in the Carnegie exhibit were procured properly.

Haas said an advisory panel researched the exhibit for months before it opened and that Carnegie officials "ultimately felt assured that the bodies in the exhibit were people who died from natural causes and that were acquired by legal means."

Atlanta-based Premier Exhibitions has provided the bodies for the Carnegie exhibit and similar exhibits such as the "Body Worlds" show at the Milwaukee Public Museum and "Bodies ... Revealed," shown in New York before moving on to Cincinnati.

New York Attorney General Andrew Cuomo has said he will investigate where the bodies came from, and Premier Exhibitions said it will cooperate.