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. Last week, Capt. Jose Luis Sanchez entered a guilty plea. Sanchez admitted to providing shipping route information to Francis' company in exchange for plane tickets, hotels and prostitutes.

Dusek also accepted hotel stays and prostitution services in exchange for providing confidential ship schedules to Singapore-based Glenn Defense Marine Asia Ltd., or GDMA, according to the plea agreement. The company has provided food, fuel and supplies to U.S. Navy ships in Asia for 25 years.

Dusek is accused of accepting the bribes between January 2009 and February 2011. He faces up to five years in prison. His lawyer declined to comment outside the courtroom.

Francis has pleaded not guilty to conspiracy to commit bribery. He was arrested in 2013 on a trip to San Diego.

Sanchez became the highest-ranking Navy official to plead guilty in the case after Daniel Layug, a petty officer who acknowledged providing classified shipping schedules and other internal Navy information to Francis.

He faces a maximum penalty of 20 years in prison when he is sentenced March 27 for bribery and conspiracy to commit bribery.

Sanchez acknowledged taking bribes valued between $30,000 and $120,000 from 2009 to 2013, prostitute services, $7,500 to travel from Asia to the U.S. and five days at Singapore's luxury Shangri-La Hotel, according to a 24-page plea agreement. In exchange, he provided classified Navy ship and submarine schedules and other internal information to Francis.

Cmdr. Michael Vannak Khem Misiewicz, has pleaded not guilty to accepting bribes in exchange for providing confidential information to Francis. He was indicted last week on an additional seven counts of bribery.

An agent with the Naval Criminal Investigative Service, John Beliveau II, and a manager for the contractor, Alex Wisidagama, who is Francis' cousin, have pleaded guilty. Another GDMA manager also pleaded guilty.