A defense contractor accused of slipping envelopes stuffed with more than $30,000 in cash to a U.S. Navy official appeared Monday in federal court in Washington and pleaded not guilty to a charge of bribery.

Frank Rafaraci, 69, the chief executive of Multinational Logistics Services (MLS), a major U.S. Navy contractor, was arrested Sept. 27 on the Mediterranean island of Maltagoo in an operation jointly planned by U.S. and Maltese authorities. He voluntarily returned to the United States on Monday to face the charge against him and was released on $5 million bond.

Until recently, MLS played a key role in U.S. Navy operations worldwide, having been awarded about $1.3 billion in contracts to service U.S. warships in foreign ports since 2010. The Navy stopped doing business with MLS after Rafaraci's arrest last month.

In an affidavit filed as part of a warrant for Rafaraci's arrest, a federal agent for the Defense Criminal Investigative Service accused MLS of defrauding the Navy of at least $50 million by inflating invoices for port services between 2011 and 2018.

The allegations against Rafaraci and MLS resemble the "Fat Leonard" scandal that has rocked the Navy since 2013. In that case, a rotund Malaysian defense contractor, Leonard Glenn Francis, pleaded guilty to bribing scores of Navy officials with cash, prostitutes and extravagant meals so he could overcharge the Navy for port services in Asia.

According to court records and interviews, federal authorities have been scrutinizing MLS for the past five years. One of the lead investigators is also a senior agent in the Fat Leonard case. The Navy relies on private contractors to resupply and refuel its vessels in ports around the globe.

Much of the investigation into MLS remains under wraps. According to court papers, an unnamed U.S. Navy official pleaded guilty in June to taking bribes from Rafaraci. But the official's identity and his criminal case file remain under seal because he is cooperating with the government.

Court papers allege that Rafaraci met with the unidentified Navy official at the Diplomat Hotel in the Persian Gulf kingdom of Bahrain in August 2015, handed over an envelope stuffed with $20,000 in cash and told the official to "keep up the good work." The official worked as a liaison officer for the U.S. 5th Fleet, which is headquartered in Bahrain.

In 2018, Rafaraci met the same Navy official at a Miami hotel and passed him another envelope that contained $13,500, court records show.

Rafaraci, a dual U.S.-Italian citizen, voluntarily arrived in the United States for his court appearance after the Justice Department's efforts to extradite him from Malta hit a wall. U.S. officials had sought to keep him in custody after his Sept. 27 arrest, arguing that he was a flight risk. But judges in Malta released him and ruled that U.S. and Maltese law-enforcement authorities had not followed proper legal procedures.

Michael R. Sherwin, an attorney for Rafaraci, said the businessman was arrested in Malta "as a result of a lure operation." Although Rafaraci could have continued to contest the U.S. extradition request, Sherwin said his client has been cooperative.

"He told me he wanted to face and interface with the Department of Justice to answer all these questions," Sherwin said Monday in federal court. "He wanted to talk to the United States and resolve this matter."

U.S. Magistrate Judge G. Michael Harvey approved Rafaraci's release Monday on $5 million bond on the condition that he surrender his passports, not leave Washington, stay away from the Italian Embassy and submit to electronic monitoring.

Federal authorities had originally charged Rafaraci with conspiracy to commit bribery, wire fraud and money laundering, as well as one count of bribery. But the indictment unsealed Monday charged him only with bribery.

During Rafaraci's hearing, U.S. prosecutor Justin D. Weitz said the decision to drop three of the charges reflected "some things that have happened over the last few weeks," but did not elaborate.