WASHINGTON — The U.S. Secret Service has placed an agent on leave after an African-American employee reported finding a noose hanging at the service's main training facility outside the nation's capital.

The service has acknowledged "an allegation of misconduct" at its J.J. Rowley Training Center in Beltsville, Md., and that it placed the employee on administrative leave last week, pending the outcome of an investigation. The employee is a veteran agent with the Secret Service, according to fellow agents.

The noose was found by an African-American officer in the uniform division of the service during the week of April 14, according to those familiar with the alleged incident. That division protects the White House and surrounding grounds.

The discovery comes as U.S. Magistrate Judge Deborah A. Robinson considers whether to sanction the Secret Service for failing to turn over evidence in a long-running discrimination lawsuit filed by Atlanta native Reginald G. Moore. Her decision is expected next month.

Moore and nine other plaintiffs contend that the Secret Service created a racially hostile atmosphere that tolerates discrimination and routinely discriminates against black agents seeking promotion in favor of white agents who score lower on promotional exams.

Nearly 60 black agents have submitted sworn statements to the court in support of the lawsuit's allegations.

Robinson has already sanctioned the service three times since the discovery process of the lawsuit began 3 1/2 years ago.

The African-American officer who found the noose at the training center reported the incident to his supervisor and it was sent up the chain of command. He declined to comment for this story.

Cox Newspapers asked the agency about the noose allegation.

"In response to your question, there has been an allegation of misconduct at our training center," said Edwin M. Donovan, assistant special agent in charge of government and public affairs.

"The employee involved has been placed on administrative leave pending an investigation by our Office of Professional Responsibility, which serves as the agency's internal affairs office," Donovan said. "At the conclusion of the investigation, additional information may be available."

Co-workers, who said they could not speak on the record because of Secret Service rules, said the suspended employee is a white man.

The African-American officer who allegedly found the noose is not part of the lawsuit, but the lawyers representing the plaintiffs say it reveals how the "good ole' boys network" at the service works to intimidate black employees.

"We are appalled but unfortunately not surprised that a noose was prominently displayed recently in a Secret Service training center," said Jennifer Klar, a lawyer with Relman & Dane who is representing the plaintiffs with lawyers from Hogan & Hartson for free.

"This incident of racial hatred is troubling in an agency that has the important duty of protecting world leaders of all races, including our own leaders such as (presidential candidate) Barack Obama and (Secretary of State) Condoleezza Rice," Klar said.

"This racist incident is a reminder that long-time discrimination in the Secret Service has created an atmosphere where such hateful acts occur all too regularly," Klar said.

"It is time for the Secret Service to put a stop to acts of racism by addressing and healing the racially charged environment that has been created over the years," Klar said.

The service denies the allegations and is now appealing all of the sanctions issued by Robinson.

The Office of Professional Responsibility, previously called the inspection division, will investigate the noose allegation. It figured prominently during the discovery process of the lawsuit as well.

Carrie Hunnicutt, an inspector in charge of searching for documents sought in the lawsuit, testified in February that she destroyed original evidence sought by the plaintiffs by placing documents in a "burn bag" just two days before she was scheduled to testify in the case.

Justice Department lawyers defending the service have said that the destroyed documents should not be considered lost evidence because Hunnicutt transferred information from the documents to a computer database.

But the plaintiffs lawyers contested that assertion, arguing that no one will ever know if the database is complete because the original evidence is destroyed.

The Secret Service has fought the lawsuit each step over the past eight years.

"The Secret Service is extremely proud of the accomplishments of our diverse work force and our record on diversity," said Eric Zahren, a spokesman for the service in an e-mail document defending the service from the accusations in the lawsuit.

"The Secret Service has not and will not tolerate discrimination of any kind," Zahern said. "We are extremely proud of the contributions of our diverse work force and we will continue to promote the most qualified people."

Moore, the lead plaintiff in the case who grew up amidst the civil rights movement in Atlanta, was promoted after filing his lawsuit in 2000. He is now in the service's senior executive service.

Moore said that he will keep fighting until the promotional system is permanently changed so that all agents of all colors have an equal chance of promotion.