SAN DIEGO » A second Navy captain pleaded guilty to conspiracy to commit bribery Thursday in a massive scheme involving a Malaysian defense contractor accused of bilking the U.S. military out of at least $20 million.

Capt. Daniel Dusek entered the plea Thursday in his first appearance in federal court in San Diego and waived his right to present his case before a federal grand jury.

His plea comes the same day the key figure in the case — defense contractor Leonard Glenn Francis, known as "Fat Leonard" — is scheduled to change his not-guilty plea.

The scandal is considered one of the worst corruption cases to rock the Navy in years.

Dusek is the fourth Navy officer charged in the case.

All the officers have been accused of providing classified information to the Singapore-based Glenn Defense Marine Asia Ltd., or GDMA, which has provided food, fuel and supplies to U.S. Navy vessels in Asia for 25 years. In exchange, prosecutors say Francis’ company provided lavish hotels rooms, prostitutes and plane tickets.

Three of the Navy officers have pleaded guilty and are scheduled to be sentenced. Cmdr. Michael Vannak Khem Misiewicz has pleaded not guilty to conspiracy to commit bribery. He is scheduled to be arraigned Friday on additional counts of bribery.

Prosecutors say GDMA asked captains re-route ships to ports owned by Francis or to small ports where they could impose fake port fees on the Navy.

After Dusek got a U.S. aircraft carrier re-routed to a Malaysian port owned by Francis in 2010, the defense contractor said in an email that the captain "is a golden asset to drive the big decks (aircraft carriers) into our fat revenue GDMA ports," according to the plea agreement.

Dusek told a company manager that he "wasn’t worried about the security one bit," according to the plea agreement.

Dusek served as deputy director of operations for the 7th Fleet and later commanding officer of the amphibious assault ships USS Essex and USS Bonhomme Richard. He admitted to accepting the bribes between January 2009 and February 2011. He was released after agreeing to up his $250,000 Oregon home as bond. He faces up to five years in prison. He and his lawyer declined to comment outside the courtroom.

Dusek, who remains on active duty working a desk job at Coronado naval base, has agreed to pay $30,000 restitution to the Navy.

After Francis was arrested in 2013 on a trip to San Diego, Dusek deleted the contents of his email accounts to avoid detection by law enforcement, according to the plea agreement.

An agent with the Naval Criminal Investigative Service, John Beliveau II, who admitted to keeping Francis abreast of the investigation in exchange for hotel stays and prostitution services, pleaded guilty in the case, as have two GDMA managers, including Alex Wisidagama.