A US navy investigator faces up to 20 years in prison after admitting sharing secrets with the target of a probe in exchange for prostitutes, cash and luxury travel.

John Bertrand Beliveau Jr., 44, a special agent with the Naval Criminal Investigative Service, pleaded guilty Tuesday to participating in a massive international fraud and bribery scheme.

Specifically he admitted regularly searching NCIS databases for details of probes into Malaysian businessman Leonard Glenn Francis -- known as "Fat Leonard" -- to help him dodge investigators.

"Instead of doing his job, John Beliveau was leaking confidential details of investigations to the target himself," said US Attorney for southern California Laura Duffy, after the plea hearing in San Diego.

"This is an audacious violation of law for a decorated federal agent who valued personal pleasure over loyalty to his colleagues, the US Navy and ultimately his own country."

He faces up to five years for conspiracy to commit bribery, and 15 years for bribery, according to Duffy's office. A sentencing hearing is due on March 7, although his lawyers say that will likely be delayed.

Beliveau is one of five Navy officials and civilian contractors implicated so far in a widening corruption case involving hundreds of millions of dollars of Navy contracts.

Glenn Defense Marine Asia (GDMA), a Singapore-based firm, is accused by federal authorities of offering prostitutes and payoffs to secure lucrative government contracts to resupply naval ships.

Its chief executive, Francis, is charged with conspiring to bribe naval and government officials.

Federal prosecutors allege naval officers divulged confidential ship movements to GDMA's Francis and diverted vessels to ports requested by the businessman.

Francis then allegedly overcharged the US government to supply the ships with food, fuel, water and other items.