The Britain-based auction house sold the brown quartzite head depicting King Tut for more than 4.7 million pounds ($5.9 million).
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Egypt’s National Committee for Antiquities Repatriation says in a statement late Monday that it hired a British law firm to file a lawsuit against Christie’s, saying the auction house did not provide documents proving ownership.
Christie’s has denied any wrongdoing, saying it carried out “extensive due diligence” to verify the provenance of the statue and had “gone beyond what is required to assure legal title.”
The committee also criticized British authorities for not supporting its claim to the sculpture.