Updated

The first conviction in a massive bribery scandal that has ensnared six U.S. Navy officials could lead to an expanded probe if a senior Navy criminal investigator who pleaded guilty cooperates with authorities as part of his plea agreement.

Naval Criminal Investigative Service agent John Beliveau II entered a guilty plea Tuesday in federal court in San Diego to bribery charges stemming from the multimillion-dollar fraud probe targeting a Malaysian defense contractor.

Beliveau, who faces a maximum sentence of 20 years when he's sentenced March 7, said he is sorry for what he's done.

"I'm here to do the right thing, and that's what I did today," Beliveau, 44, said after the hearing.

His attorney, Gretchen von Helms, declined to say whether her client would now assist the investigation, saying only he is "ready to prove he is honorable."

Beliveau acknowledged keeping contractor Leonard Glenn Francis abreast of the yearslong fraud investigation that NCIS agents were conducting on Francis' company, Glenn Defense Marine Asia Ltd., or GDMA.

In exchange, Francis paid for plane tickets, hotels and prostitutes for Beliveau, according to the plea agreement. Francis has pleaded not guilty in the case that alleges GDMA overbilled the Navy by at least $20 million for port services. GDMA has provided fuel, food and supplies for Navy ships for 25 years.

According to the plea, Beliveau gave Francis detailed advice on how to thwart the investigation, leaking the names of witnesses and downloading hundreds of pages of confidential NCIS files to share with him.

Two Navy captains have also been charged in the case. Prosecutors allege they provided Francis with confidential ship route information or directed the movement of Navy vessels to Asian ports with lax oversight so the company could inflate costs and invent tariffs by using phony port authorities.

In exchange for the assistance from the Navy officials, Francis, known in military circles as "Fat Leonard," lined up prostitutes, hotel stays and tickets to shows, including a Lady Gaga concert in Thailand, according to a criminal complaint.

"This isn't only bad news for Leonard Glenn Francis, but I suspect there are a number of yet unnamed Navy people who are (and should be) worried," Michael T. Corgan, a Vietnam veteran who teaches international relations at Boston University, said in an email.

"Something of the scope that this scandal embraces didn't happen without a reasonably widespread acceptance of bad practice," he wrote.

Francis was arrested in September. His cousin, Alex Wisidagama, a company manager who was also arrested, also has pleaded not guilty in the case. Navy Cmdr. Jose Luis Sanchez and Cmdr. Michael Vannak Khem Misiewicz have entered not guilty pleas as well.

Francis and Beliveau exchanged thousands of text messages, and at one point, the contractor bragged to an associate in an email: "'I have inside Intel from NCIS and read all the reports,'" according to court documents.

When authorities became aware that Beliveau was leaking information, they planted bogus reports in NCIS files, including one indicating that they were dropping the case against Francis, according to the prosecution.

Shortly after that, Francis flew to San Diego, believing he was meeting with Navy officials for business and was arrested, according to court records. Beliveau, who worked for NCIS for 11 years, was taken into custody that same day in Virginia.