A government chemist who testified against one of the Washington sniper suspects has made numerous racial remarks and has an office so sloppy it has raised concerns of contaminated evidence, according to information the government has possessed for more than a decade.

The Virginia prosecutor handling the trial of sniper defendant John Muhammad (search) said Thursday he wasn't told by the government of the information, obtained by The Associated Press, before he put Edward Bender on the witness stand last week. "And I'm not aware of it today," Paul Ebert said.

Muhammad's attorneys, who made their closing arguments Thursday, declined comment. Lawyers and prosecutors in the case of the other sniper defendant, Lee Boyd Malvo (search), said they, too, weren't told about Bender's situation.

The government is required under two Supreme Court rulings, Brady v. Maryland and Giglio v. United States, to provide defendants with all relevant information affecting their case, including derogatory information that could be used to challenge prosecution witnesses.

FBI (search) and Justice Department documents obtained by AP detail testimony from colleagues and supervisors that Bender made racist comments that raised concerns by at least one colleague about his impartiality in cases.

A supervisor and "Bender continually and loudly expressed strong racial prejudice using such words as 'jungle bunnies' and 'niggers' repeatedly," a 1991 FBI memo stated, recounting allegations from one of Bender's lab colleagues.

In government interviews, Bender never admitted using those words but acknowledged making racial comments. He insisted it never affected his work.

"If you ask me if I've ever used racial statements, I'll say, of course, you know," Bender told Justice officials in 1996. "But do I have, you know, is there like some kind of history that you would look and say, oh, this is black, he's got to be guilty? No."

The Bureau of Alcohol, Tobacco, Firearms and Explosives, which currently employs Bender, said Thursday it was aware of the documents and was meeting with lawyers. "As these cases are in litigation, further comment is inappropriate at this time," spokesman Bill King said.

The documents state that Bender avoided possible punishment or further investigation when he transferred from the FBI to ATF.

Bender also told Justice officials he kept a messy office near his lab analysis area where explosives evidence occasionally was brought. "I mean that would, in the dictionary definition, probably be sloppy," he said.

He told investigators he took precautions to avoid contamination of evidence but that it was possible evidence he brought from the lab to his office could have caused contamination. "There's always a possibility," Bender said.

Former FBI lab supervisor James Corby told the investigators, "Ed Bender's a very good chemist. He's sloppy though. He is sloppy." Frederic Whitehurst, another supervisor, agreed.

Bender "would not label instrumental output, follow protocols, wash glassware, clean the laboratory, leave his work area in clean condition though he worked trace analysis, was generally insubordinate and openly and extremely racially biased using racial slurs often in my presence," Whitehurst said.

Bender, now an ATF chemist, testified on behalf of prosecutors last week at the trial of Muhammad, who along with Malvo is black. The chemist testified he found residue that indicated a gun was fired from the trunk of their car as prosecutors have alleged.

Craig Cooley, one of Malvo's attorneys, said he was unaware of the Bender allegations but probably wouldn't challenge his findings.

Richard A. Hibey, a former federal prosecutor, said the evidence of Bender's specific racial statements should have been disclosed by the government to defense lawyers, comparing it to racist comments Los Angeles police detective Mark Fuhrman was questioned about in the O.J. Simpson case.

"What has happened here is there is a black defendant and there is a witness in the past who apparently made racist remarks and who by making those statement has opened himself up to cross-examination on his credibility," Hibey said.

The racism allegations first surfaced in 1991 from Whitehurst, a whistleblower on problems inside the FBI lab. Justice Department documents said the comments were confirmed by numerous witnesses.

"Our investigation confirms that Bender inappropriately made racial comments while employed as a technician in the laboratory, but we do not find evidence that his remarks or his racial views affected his work in particular cases," the Justice inspector general reported in 1996.

A January 1991 memo from the FBI internal affairs unit said Bender's racial comments often occurred in conversations with a supervisor named Terry Rudolph.

"During numerous conversations with SSA Rudolph, Rudolph acknowledged Bender's strong racial prejudice," the memo stated. "His attitude and suggestions at the time made it clear that Bender's racial prejudice drove his work product and had effected even who could receive training," the memo stated, relating Whitehurst's concerns.

FBI lab worker Russell A. Gregor provided a sworn statement to FBI internal affairs investigators in December 1991 that "I have had occasions where I have heard Ed Bender make remarks which I would consider racial remarks."

"He joked a lot about blacks' facial features," Gregor said. "I do not consider Bender to be a serious bigot. He would make offensive remarks about anybody."

A 1992 FBI interview report quoted Bender as recounting "discussions which occurred after either he or Rudolph saw a street person out the window who was generally black. The comments would include a question as to whether that individual was formerly the mayor of a given city."

In a 1996 interview with Justice officials, Bender said, "I'm sure that at some period of time I have made racial comments, sure. But they were probably used in the context with maybe a joke or something like that. But there was no overt racism there."