SAN DIEGO -- A former defense contractor accused of bribing disgraced ex-congressman Randy "Duke" Cunningham was a straight-shooter and generous boss who was not motivated by greed, his former assistant testified Thursday.

Brent Wilkes, 53, is charged with conspiracy, wire fraud, bribery of a public official, money laundering and unlawful monetary transactions. He could face up to 20 years in federal prison if convicted.

Prosecutors allege the Poway businessman bribed Cunningham with $700,000 in cash and expensive gifts -- including vacations, Super Bowl tickets, $300-an-hour prostitutes -- and falsified loan and boat payments on his behalf to land $85 million in Department of Defense contracts from 1997 to 2004.

Kristin Ivancich, the first witness called by the defense, testified that she was hired in 2001 as a receptionist at the defendant's document-scanning company, ADCS Inc., and eventually worked her way up to executive assistant.

Defense attorney Mark Geragos asked Ivancich whether she thought money and greed were motivating factors for Wilkes as he built his small business.

"I don't believe it was, no," the witness replied.

Ivancich said Wilkes was a great boss, "a good man to work for" and was generous and a straight-shooter.

The witness said she didn't have the impression that Wilkes was dishonest.

Ivancich said Wilkes' nephew, Joel Combs, who testified for the prosecution, had a reputation as a "ball-dropper" and someone who didn't follow through on his tasks.

On cross-examination, Ivancich told Assistant U.S. Attorney Sanjay Bhandari that she was aware of some of the meals and free tickets that Wilkes gave to Cunningham, but wasn't worried about any improprieties.

Bhandari asked Ivancich whether she knew Wilkes spent $40,000 for a weeklong vacation for himself at a Scottish castle in 2003.

The witness said she wasn't aware of how much the trip cost, but said Wilkes was a hard worker and was entitled to spend his money the way he wanted.

Ivancich bristled when the prosecutor asked her if she knew that Wilkes hired prostitutes for himself and Cunningham during a 2003 retreat to a resort in Hawaii.

"I never knew of any such thing to happen," the witness testified.

Geragos is expected to call a number of former Cunningham chiefs of staff to the witness stand when the trial resumes Tuesday and wrap up his case the following day.

Closing arguments could begin as early as Wednesday afternoon.

Outside court, Geragos would not say whether Wilkes or Cunningham would testify.

The attorney was asked his reaction to the prosecution's decision not to call the former congressman as a witness.

"They know that he wouldn't support their theory (of the case)," Geragos told reporters.

Cunningham, who was a Navy fighter pilot during the Vietnam war, pleaded guilty in November 2005 to accepting more than $2.4 million in bribes and was sentenced to more than eight years in federal prison.

Combs testified Wednesday that Wilkes not only paid for the prostitutes in Hawaii but also paid for other expensive trips for Cunningham, including fully expensed retreats to Coeur d'Alene, Idaho, and Key Largo, Fla.

Combs said his uncle told him that the goal during the trips was to "show Duke a good time."

Wilkes also bought expensive meals, computers and computer software for Cunningham, Combs said.

When Assistant U.S. Attorney Phillip Halpern asked Combs what Wilkes got in return, the witness replied, "Duke's support for earmarks" and "Duke's ability to solve problems" with getting money for contracts from the Department of Defense.

Former Wilkes consultant Mitchell Wade, who last year pleaded guilty to conspiracy, fraud and other charges, testified last week that pressure from Cunningham on the Defense Department meant "hundreds of thousands of dollars" for his Washington, D.C.-area consulting business and millions of dollars in defense contracts for Wilkes' company.

Geragos told the jury in his opening statement that Wade was responsible for 90 percent of the bribery scandal involving Cunningham.

Much of what Wilkes was doing in Washington, D.C., was "business as usual," Geragos said.

Wade testified that he personally bribed Cunningham to secure defense contracts.

The witness said that in 2001, he started cultivating his own relations with Cunningham in hopes of starting his own contracting firm to compete with Wilkes.

Wade said Cunningham asked for $50,000 and he gave it to him, but made the check out to Coastal Capital Corp. so nobody would suspect it came from him.

He said he bought a $140,000 yacht for Cunningham, called the "Duke Stir," and registered it in his name.

Wade said he hid the fact that he bought Cunningham's home in Del Mar for an inflated price of $1.675 million and then sold it months later for $600,000-$700,000 less than what he originally paid for it.

Wade said he engaged in the home-buying scheme because Cunningham wanted extra cash to purchase a $2.6 million home in Rancho Santa Fe.

New York-based mortgage broker John Michael is awaiting trial on charges of obstruction of justice, accused of attempting to influence and impede a grand jury investigation.

He's accused of providing false and misleading testimony regarding Wilkes' role in paying off the $500,000 second mortgage on Cunningham's Rancho Santa Fe mansion.