Defense contractor Leonard Francis, right, is shown in this courtroom sketch with his attorney Patrick Swan, Judge David Bartick and Prosecutor Robert Huie in an November appearance in court in San Diego. (KRENTZ JOHNSON/REUTERS)

The House Oversight and Government Reform Committee has opened an investigation into an unfolding Navy sex-and-bribery scandal and other allegations of contracting fraud.

In a letter sent this week to Navy Secretary Ray Mabus, the committee chairman, Rep. Darrell Issa (R-Calif.), said he was concerned that the Navy’s investigations and reviews “will not go far enough.” He said the Navy needed to strengthen its oversight policies further “to prevent the waste, fraud and mismanagement of millions of additional taxpayer dollars.”

Issa ordered the Navy to share copies of all records of contracts it has signed since 2009 with Glenn Defense Marine Asia, a Singapore-based firm that resupplied and serviced Navy vessels throughout Asia until its chief executive was arrested in a federal sting operation in September.

The executive, Leonard Glenn Francis, a Malaysian native known as “Fat Leonard,” has been imprisoned since his arrest in California on corruption-related charges. A senior agent with the Naval Criminal Investigative Service has pleaded guilty to giving sensitive law-enforcement information to Francis in exchange for prostitutes and cash.

Two Navy commanders have been arrested on similar charges and are awaiting trial. In addition, the Navy is investigating two admirals and two captains for their connections to the firm.

Read court filings

Glenn Defense Marine and its president, Leonard Glenn Francis, are principal characters in one of the biggest contracting fraud investigations in the Navy's 238-year history, with accusations of bribes involving prostitutes and cash. Explore the government's evidence.

• U.S. attorneys offer details of the investigation, argue Francis is a flight risk

• Government lays out case on conspiracy between Francis and Michael Vannek Khem Misiewicz

• Affidavit on ties between Francis and Jose Luis Sanchez

In a statement, Mabus said he welcomed the congressional inquiry and would work with lawmakers.

“I’m proud of the work that the Naval Criminal Investigative Service has done to ferret out the alleged fraud and corruption carried out by GDMA and of the action our leaders have taken to strengthen our acquisition integrity and oversight processes,” he said.

In addition to the Justice Department’s criminal investigation into Navy officers and Glenn Defense Marine, the Navy is conducting an internal probes into individual officers and its contracting procedures.

The House Oversight Committee is one of the most powerful investigative panels in Congress. It can compel testimony and issue subpoenas on just about any target.

Issa’s letter, however, did not make clear whether the committee intends to conduct a major probe into the Navy’s contracting business or whether it might just amount to a preliminary review.

Issa noted that the Navy was rocked by another contracting scandal in 2011 and that Mabus appointed a special review panel afterward to prevent such problems from happening again.

“Nearly three years after this pledge, however, significant problems remain and it does not appear that the process has improved significantly,” he wrote.