A political consultant with a colorful history said Wednesday that the FBI asked him to be a paid informant in the investigation of Nathan A. Chapman Jr. and questioned him extensively about Chapman's relationship with former governor Parris N. Glendening.

The consultant, Julius Henson, said he rejected the agent's request.

Also Wednesday, Judge William D. Quarles Jr. ruled that the defense cannot mention U.S. Attorney Thomas M. DiBiagio's recent request that his prosecutors deliver "front-page" indictments in public corruption and white-collar crime cases. DiBiagio's directive, which drew a rebuke from his superiors at the Department of Justice, was issued long after Chapman was indicted and, thus, is not relevant in the trial, the judge said.

Henson said he and the agent, Steven Quisenberry, spoke for perhaps 45 minutes in January 2003. He said Quisenberry's questions focused so much on Glendening (D) that he was unsure which man was under investigation. Henson testified that when he turned down Quisenberry's request that he act as an informant, the agent said, "We could help you with your candidates."

He said he told the agent that his research capabilities were superior to those of the bureau. "I told him I could tell him everything he's done up to 15 minutes ago in his life and I didn't need the FBI's help," Henson said, testifying for Chapman's defense at U.S. District Court.

On cross-examination, Henson said the agent who offered the bureau's research services gave his age as 49, and Henson acknowledged that Quisenberry is significantly younger. The prosecution suggested that Henson might have mixed up Quisenberry and agents he had spoken with about unrelated matters. Henson did not explain the discrepancy but maintained that Quisenberry had made the offer.

Quisenberry and a spokesman for the FBI declined to comment. When Quisenberry testified earlier in the trial, he was not asked whether he had made such an offer.

Chapman, who once managed more than $140 million from the state pension fund, is accused of defrauding the fund by improperly investing a portion of that money in his own struggling companies, losing nearly $5 million from the fund in the process. The government also alleges that he improperly took more than $500,000 from those companies, failing to account for it as income.

Although he excluded evidence concerning the DiBiagio controversy, Quarles ruled that the defense may continue to pursue the theme that the government was particularly interested in Chapman's ties to officials in the Glendening administration. The defense has sought to suggest that Chapman was a consolation prize in a failed pursuit of the former governor.

The defense argued unsuccessfully that DiBiagio's May directive to his staff, and a subsequent e-mail in which he said he was "embarrassed" that the office had not convicted an elected official of corruption since 1988, shed light on the government's motivation in bringing the case. Prosecutors argued that the issue was a mere distraction from the question of Chapman's guilt.

Henson testified that Chapman had sought his advice on a possible run for the U.S. Senate, either in 2004 or 2006. He said Quisenberry "was not happy" with his observation that he believed Chapman was guilty of no wrongdoing.

"It struck me that Mr. Quisenberry was not only adamant but he had, I felt, a real dislike for Mr. Chapman," Henson said.

Henson said the state pension fund had lost vast sums in a market downturn that occurred immediately before Chapman, with heavy backing from the pension fund, took his online financial services company public in June 2000. He described the loss in assets under Chapman's management as "dog food money" by comparison.

"I said to Mr. Quisenberry, 'Why are you guys picking on this guy?' "

The jury heard little of Henson's storied career as a political consultant and nothing about a widely reported incident in 2002 in which he called then GOP gubernatorial candidate Robert L. Ehrlich Jr. a "Nazi." After the remark, Democrat Kathleen Kennedy Townsend's campaign fired Henson.

On Wednesday, Henson offered blunt assessments of deal-making in Maryland's political circles and said he had told Quisenberry that Glendening hadn't done anything illegal.

He said Chapman, after arranging a fundraising event for Glendening at Camden Yards, once asked him what might be sought in return. "I always advise people to get a contract, and if it can be no-bid, that's good, too," Henson said.