A San Diego museum will be told to return to Thailand ancient artefacts found in a high-profile 2008 US federal investigation into allegations the museum had received looted cultural treasures, authorities said on Friday.
Dozens of pieces of pottery and other items from the prehistoric settlement of Ban Chiang, a Unesco World Heritage Site, were tagged as evidence at the Mingei International Museum during a series of raids that targeted four California museums.
The Mingei artefacts had been left in the museum's vaults for the last seven years.
"After a careful review of the matter, we are planning on lifting the 'seizure in place' order and directing the museum to repatriate the artefacts that we believe were illegally obtained," said Thom Mrozek, spokesman for the US Attorney's Office in Los Angeles.
"In short, the museum will soon be informed that it should not have possession of the items and it should take immediate steps to do whatever it can to return the items to their country of origin."
Jerry Coughlan, an attorney for the Mingei, said the museum could not comment on the matter because it had yet to formally receive those instructions.
The Mingei has denied wrongdoing in accepting the artefacts, but has tightened its screening procedures for donations since the federal investigation, according to Coughlan. No charges have been filed against the museum or any staff members.
After a five-year investigation that featured an undercover operative, federal prosecutors alleged that looted artefacts were sold to clients who then donated them to museums at overstated appraisals to secure higher tax breaks.
Last year, hundreds of pieces of Ban Chiang tools, beads, pottery and bronze items at the Bowers Museum in Santa Ana, California, were returned to Thailand under a non-prosecution agreement between the museum and the US attorney, according to Mr Mrozek.