A former Maryland pension fund official testified Monday that despite assurances of protection from the U.S. attorney's office, she was fired from her state job last year after cooperating in a federal investigation of investment banker Nathan A. Chapman Jr.

Carol Boykin, who was the chief investment officer at Maryland's state pension agency, said that U.S. Attorney Thomas M. DiBiagio told her in February 2002 that her job would be protected as long as she remained a government witness in the case.

In April 2003, she e-mailed prosecutors saying that she was being fired by the board that oversees the Maryland pension fund. She told DiBiagio and Assistant U.S. Attorney Jefferson Gray, a prosecutor in the Chapman case, that she believed the firing was in retaliation for her grand jury testimony, which had been "damaging to several [pension board] members."

"Tom told me that my job was protected" for the duration of the case, Boykin wrote in the e-mail. "I now need to know what my options and protections are as a witness for you."

Testifying in U.S. District Court, Boykin said that DiBiagio "did not do anything to alter the course" of her termination.

"He did not protect my job," she said.

Boykin's remarks about DiBiagio came on cross-examination by defense attorney Marc Rothenberg in the fifth week of Chapman's trial on charges of wire fraud, mail fraud, securities fraud and other crimes. The government alleges that Chapman, a former president of the University System of Maryland Board of Regents, improperly arranged for state pension money under his control to be invested in an Internet company he was taking public.

The value of the stock in eChapman.com fell sharply after the company went public in June 2000. Prosecutors allege that the scheme ultimately cost the state pension fund -- which benefits teachers, police officers, judges and others -- nearly $5 million.

Through a spokesman, DiBiagio declined to comment on Boykin's testimony. Gray also declined to comment.

By 1999, a company Chapman controlled had been given $140 million in state pension assets to manage. Under questioning by the prosecution Monday, Boykin testified that in 2001 Chapman requested more money from the pension fund. She said she "didn't take it seriously" because the assets he already was managing were not performing well.

When she told an agency investment committee about Chapman's request, she said, "several of the members laughed, others took it seriously."

She said in her e-mail to DiBiagio that when the pension board fired her in April 2003, it did not give her a detailed reason.

One of the board's members, Bruce Harrison, told her that with the exception of his vote, the board was unanimous in its decision, Boykin said in her e-mail. She said Harrison told her that the board member who made the motion to fire her had lost confidence in her because she had not informed the board about "the Chapman matter."

Outside the courthouse, Boykin said: "Everything I've done in this matter has been in the best interest of the pension plan's beneficiaries and participants and in an effort to obey the law. . . . I'm fully supportive of the U.S. attorney's efforts in this matter, and I'm convinced justice will prevail."

Boykin, who had worked for the agency since 1999, was paid more than $116,000 in her position. She has since taken a job with a consulting firm, defense attorneys said outside court.