SAN DIEGO (REUTERS) - A business executive charged in connection with a US Navy contracting case that has exploded into a corruption scandal pleaded guilty on Tuesday to one count of conspiring to defraud the United States.

Alex Wisidigama, whose cousin ran a Singapore-based company at the center of a military contracting scandal, entered his plea in US District Court in San Diego as part of an agreement with prosecutors.

The scandal is one of several that has wracked the military in recent months, prompting US Secretary of Defense Chuck Hagel to say in February that he would appoint a senior officer to report directly to him on matters of ethics.

In the San Diego case, prosecutors say the maritime services firm Glenn Defense Marine Asia, led by Wisidigama's cousin Leonard Glenn Francis, bribed Navy officials to get information, and filed false invoices in contracts worth millions of dollars at ports across Asia.

The investigation into the case has led to charges against two navy commanders and an investigator, along with Wisidigama and his cousin Francis.

In the plea deal, Wisidigama admitted to helping the company submit false quotes for incidental expenses as part of a scheme to overbill the Navy under the contracts.

Wisidagama, 38, will face a maximum sentence of 10 years in prison and a US$250,000 (S$315,937) fine at his June 13 sentencing.

Francis, a 49-year-old native of Malaysia, is accused of providing prostitutes, cash, luxury travel and concert tickets to Navy officials in exchange for information to help him win the contracts and to track the growing investigation against him.

Francis was arrested and charged with conspiracy to commit bribery, as were US Navy Commanders Michael Misiewicz and Jose Luis Sanchez and Navy criminal investigations special agent John Beliveau.

Francis has pleaded not guilty and is in federal custody in San Diego.

In December, Beliveau pleaded guilty to helping Francis obtain information about the investigation against him.