The unusual four-day trip is the latest development in a court case involving the auction house and United States officials, who are trying to help Cambodia gain possession of the statue, which it contends was looted from the temple during the chaos of that country’s civil war.
Though United States officials have intervened on behalf of foreign governments in patrimony cases, experts on cultural heritage law said it was rare for federal lawyers to visit an archaeological site abroad as part of such an effort.
Sharon Cohen Levin, the chief of the United States Attorney Office’s Asset Forfeiture Unit, and a second federal lawyer, Alexander Wilson, spent Wednesday at the temple’s remote location after first meeting with Cambodian officials in Phnom Penh.
Ellen Davis, a spokeswoman for the United States Attorney’s Office, disagreed that the trip was unusual. “Many of our cases in a variety of areas have an international component, and our prosecutors routinely travel all over the world in connection with their investigations, as required by the nature of the particular case.”
She declined to specify what aspect of the federal case drew the lawyers to Cambodia.
Cambodian and United Nations officials said the lawyers were there to collect evidence to bolster arguments that the statue was stolen in the early 1970s from a ransacked temple site in a complex known as Koh Ker.
A Cambodian government spokesman, Ek Tha, said the delegation that visited the temple included Cambodian and foreign archaeologists.
A federal judge is scheduled to rule in weeks on whether the government’s case to seize the statue can proceed to trial. In earlier arguments District Judge George B. Daniels has pressed prosecutors on what proof they had that the statue, called the Duryodhana, was taken in the 1970s.
Sotheby’s has been trying to sell the statue, valued at as much as $3 million, on behalf of its Belgian owner since 2011. The United States government says the auction house had reason to suspect that the statue had been stolen, and that it is the rightful property of Cambodia, citing laws governing antiquities adopted when the country was a colony of France.
Sotheby’s has said the statue was legally purchased in good faith from a reputable London auction house in 1975 by the owner’s husband, now deceased, who had no reason to suspect that such a sale could be bound by laws set by a government that had long passed from power.
In a statement the auction house said the trip by the lawyers “will not change critical weaknesses in the government’s case — most importantly, its reliance on hopelessly ambiguous French colonial decrees.”
Some experts saw the move as a sign that the United States government is worried about its ability to prove how and when the statue was taken.
“They are very invested in this case, and it would be humiliating to lose,” said William G. Pearlstein, an arts lawyer in New York and a former member of the American Bar Association’s International Cultural Property Committee. “I think they underestimated the requirements of the judge in proving actual theft and Cambodian ownership.”
Others said the trip had a diplomatic component and showed the United States’ commitment to an important matter for the Cambodian government.
Evan T. Barr, a former federal prosecutor and now a partner with the New York law firm Steptoe Johnson, said Ms. Levin’s trip, while not routine, made sense. “She is literally eyeballing the scene of the crime, so when she presents the case in court, she can speak from firsthand knowledge,” he said.
Ralph Blumenthal contributed reporting.