SAN DIEGO (CNS) - Two former executives of foreign defense contractor Glenn Defense Marine Asia pleaded guilty Tuesday to fraud charges for conspiring to submit bogus bids, claims and invoices to the U.S. Navy in an effort to win contracts and overcharge the Navy by tens of millions of dollars in a years- long corruption scheme.

Neil Peterson, 39, and Linda Raja, 44, both of Singapore, worked as chief deputies for defense contractor Leonard Glenn Francis to fill the coffers of their company at the expense of the U.S. Navy, prosecutors said.

Peterson was vice president of Global Operations for GDMA and Raja served as GDMA's general manager for Singapore, Australia and the Pacific Isles.

Both defendants were arrested by authorities in Singapore at the request of the U.S. government and were extradited to San Diego last October. They are scheduled to be sentenced Aug. 11.

According to their plea agreements, Peterson, Raja and other members of GDMA's management team created and submitted fraudulent bids that were either entirely fictitious, contained falsified prices supposedly from actual businesses, or fraudulently stated that the business shown on the letterhead could not provide the items or services requested.

In that manner, Peterson and Raja and other GDMA managers could ensure that GDMA's quote would be selected by the U.S. Navy as the supposed low bidder. GDMA could then control and inflate the prices charged to the U.S. Navy without any true, competitive bidding, as required, according to the government.

For example, under the direction of Peterson and other GDMA managers, false documents and inflated invoices were presented to the U.S. Navy for the visit of the USS Bonhomme Richard to Malaysia in October 2012.

The full amount billed to the U.S. Navy for the visit was $1.2 million, of which $877,413 was fraudulently inflated, according to court papers.

Peterson and Raja admitted that losses to the U.S. Navy as a result of their actions exceeded $34.8 million.

According to prosecutors, 20 Navy officials have been charged so far in the fraud and bribery investigation.

In addition, five GDMA executives -- Peterson, Raja, Francis, Alex Wisidagama and Ed Aruffo -- have pleaded guilty in the case.