WASHINGTON - A Delaware County real estate agent and close friend of former U.S. Rep. Curt Weldon who became a Capitol Hill lobbyist pleaded guilty yesterday to destroying evidence related to the FBI's investigation of Weldon.

Cecilia M. Grimes, 43, became the second close Weldon associate to plead guilty and agree to cooperate with the FBI in its corruption investigation of the 10-term Republican congressman, his Russian business associates, and others.

In part, the FBI is investigating whether Weldon agreed to support contracts for Grimes' clients "as a quid pro quo for the payment of fees" by contractors to her lobbying firm, court papers say. Authorities are also investigating Weldon's relationship with Russian energy companies.

Weldon, once a powerful and outspoken vice chairman of the House Armed Services and Homeland Security committees, has denied any wrongdoing.

Grimes' plea-agreement documents do not specify who she is cooperating against. The case is being handled jointly by public-corruption and organized-crime prosecutors.

After yesterday's hearing in federal court in Washington, Grimes' lawyer, Richard Scheff, and the prosecutor, Howard Sklamberg, declined to comment.

Grimes, of Parkesburg, Chester County, told U.S. District Judge Henry H. Kennedy yesterday that after FBI agents interviewed her in October 2006 and issued a subpoena, she tried to throw out potentially incriminating documents. These included an airplane boarding pass, a travel itinerary, Weldon campaign literature, and receipts from three of her lobbying clients.

Six days after the FBI visit, agents found those documents in garbage cans that Grimes placed on her street for a weekly trash pick-up.

Grimes also admitted yesterday that she threw her BlackBerry device into a trash can near an Arby's Restaurant in suburban Philadelphia. In court papers, Grimes admitted that she did so "for the purpose of keeping the FBI from reviewing certain e-mails that would be of the interest to the FBI."

In court, she said she discarded the device because she feared personal e-mail on the BlackBerry would end up splashed in the media. She did not elaborate.

In a statement released earlier this month, Scheff said Grimes was remorseful for destroying documents sought by the FBI but added that it would be wrong to say that Grimes committed any misconduct related to her lobbying.

Despite her lack of any Washington experience, Grimes became a registered lobbyist for several defense contractors and sought her friend Weldon's help winning contracts. One of her clients, Oto Melara, a subsidiary of a giant Italian defense manufacturer, built a factory near Philadelphia International Airport.

Under federal sentencing guidelines, Grimes faces 10 to 16 months in prison. But her term could be far less if prosecutors conclude that her cooperation is "substantial," according to her plea agreement.

Grimes is not scheduled to be sentenced until at least Jan. 23, which means an investigation that burst into public view in October 2006, deeply wounding Weldon's final reelection effort, does not appear to be on its last legs.

Weldon's lawyers, William J. Winning and Arthur T. Donato Jr., declined yesterday to comment on Grimes' guilty plea.

The other person charged in the case, Weldon's former chief of staff, Russell James Caso, is also cooperating with the FBI. He pleaded guilty to one count of conspiracy in December and was scheduled to be sentenced in May, but, as the investigation dragged on, sentencing was postponed.