The sculpture is a hulking 500-pound Khmer masterpiece that was set to be auctioned in March 2011 but withdrawn after Cambodia objected and asked for its return. Cambodia is also seeking the return of a companion piece, of a warrior called Bhima, that is on display at the Norton Simon Museum in California. Cambodia has identified the two massive pedestals where the statues once stood because their feet match the statues, which were broken off at the ankles.

Federal investigators have said the Sotheby’s statue was among thousands pillaged during civil war in Cambodia in the 1970s and that Cambodian witnesses recall seeing it in place in that era. In its amended complaint, the government said it had narrowed the date of removal to “in or about 1972” and had identified the looting ring that took it. The ring was not identified in the papers.

Prosecutors said the looters turned the statue over to a Thai middleman, and it ended up in the hands of a “collector,” but the papers do not name him. The collector is said to have sold the statue to a London dealer, Spink & Son, a major purveyor of Asian artifacts now reincorporated under the name Spink. In 1975, the statue was bought by the husband, now dead, of a Belgian woman named Decia Ruspoli di Poggio Suasa, who turned the work over to Sotheby’s for auction in 2010.

The government contends Sotheby’s left out the name of the collector who sold the statue to Spink and other details about the statue’s provenance to mask the trail of the artwork. Sotheby’s denied that, saying it left out the name of the collector because he had no role in the deal.

Douglas A. J. Latchford, an Asian art collector, donor and adviser to the Cambodian government on Khmer antiquities, said by phone from Bangkok that he is the collector referred to in the court papers.