The FBI interviewed a former campaign worker for Anthony A. Williams yesterday as part of its investigation into the massive forgeries in the mayor's nominating petitions that kept him off the ballot and forced him to wage a write-in campaign during the Democratic primary election.

Ann E. Lewis, who collected petition signatures at her Southeast Washington apartment building, met with FBI agents, according to sources familiar with the investigation. She has acknowledged that she signed as circulator a petition she did not circulate, and she said her name was forged as the collector on 14 other petitions.

Lewis, 64, would not comment on the meeting. Her attorney, Dee Hunter, said his client has been contacted by law enforcement officials but stopped short of confirming that she was interviewed yesterday.

"Ms. Lewis did not do anything wrong intentionally. Therefore, she will cooperate in this investigation just as she did with the Board of Elections," Hunter said.

Lewis is one of five campaign workers whose names the D.C. Board of Elections and Ethics referred to federal prosecutors for further investigation of their roles in the petition gathering. The board's decision denied the mayor a spot on the Sept. 10 primary ballot, which led to his last-minute, but successful, write-in campaign.

Williams won overwhelmingly during Tuesday's general election.

The other campaign workers referred to the U.S. attorney and city's corporation counsel for possible prosecution are Scott Bishop Sr., who oversaw the mayor's petition gathering process; his son, Scott Jr.; his daughter-in-law, Crystal; and Robert Yeldell.

Channing Phillips, spokesman for the U.S. attorney, said he could not comment on the investigation because it is "active and ongoing."

Kenneth J. McGhie, general counsel for the elections board, said he has fielded questions from two lawyers from the U.S. attorney's office and two FBI agents, including one who last week requested additional evidence from hearings by that began in mid-July.

"The agent called and asked for more material," McGhie said. "They're definitely working on it."

Benjamin F. Wilson, chairman of the elections board, said he is pleased that the investigation by federal authorities is underway.

"We hope and expect that a thorough investigation will ensure the prosecution of those responsible for the attempted fraud," he said.

Wilson also said he hopes that the investigation by federal officials can answer one major question still lingering after the board hearings.

"We don't know who was responsible for signing the names of individuals after the nominating petitions were turned in to the campaign," Wilson said. "I would expect this is one of the issues that the office of the U.S. attorney is investigating."

Several campaign workers said during the hearings that they turned in incomplete nominating petitions and that names were later added that they did not witness. In other instances, names of celebrities and international figures, including British Prime Minister Tony Blair and actor Kelsey Grammer, were forged on the petitions.

The elections board asked prosecutors to investigate the forgery and fraud after holding several hearings to discern how half of the signatures initially submitted by the campaign to secure Williams a spot on the ballot were forged. Williams needed 2,000 signatures of registered voters, but the campaign collected five times as many.

Before the hearings, Crystal Bishop said in an interview with The Washington Post that she had signed many petitions she had not personally circulated, a violation of elections law. But she denied that she or her husband signed the names of any voters or other circulators.

David Wilmot, attorney for the elder Bishop, said his client has not been contacted by law enforcement agents. The attorney for the younger Bishops, Vandy L. Jamison Jr., also said that his clients had not been interviewed but that he recognized that the investigation is ongoing.

Lewis was a campaign worker who allegedly signed as collector of signatures on one petition she did not personally circulate. Lewis circulated three petitions, and a fourth was circulated by her neighbor, Yeldell, who was the Ward 8 campaign coordinator.

Yeldell said he had circulated the petition in question and gave it to Lewis so she could collect the $1 per name from the campaign.

But Lewis's name also appeared to be forged on 14 other petitions that she neither circulated nor signed. The elections board has requested leniency for Lewis because she cooperated with officials during the hearings.

"I want it to be over with," Lewis said, adding that the episode which began with hearings before the elections board has been stressful. "I want my name to be cleared."

Yeldell, who continued working for Williams's campaign after the elections board hearings, said that federal prosecutors have not contacted him.

"I haven't heard a word," he said.