It has been 28 months since FBI agents descended on Delaware County in the midst of a no-holds-barred congressional race, eliminating U.S. Rep. Curt Weldon's chances of returning to Washington for an 11th term.

In October 2006, three days after media reports revealed the existence of an influence-peddling probe involving Weldon, federal agents raided the homes and business of the congressman's daughter, Karen, and his campaign adviser, Charles Sexton Jr.

But more than two years after the raids, neither the Weldons nor Sexton have been charged, and some legal observers say they may not be.

During the raids, investigators were reportedly seeking records to determine whether Weldon had helped steer nearly $1 million in foreign lobbying contracts to Solutions North America, a firm that was run by his daughter and Sexton, the longtime boss of the Springfield GOP.

Prosecutors later charged Cecelia Grimes, a lobbyist and friend of Weldon's, with destroying evidence, including the disposal of her BlackBerry in an Arby's trashcan. Russ Caso, the congressman's former chief of staff, was charged with failing to list a conflict of interest in his 2005 congressional disclosure forms.

Both pleaded guilty and agreed to cooperate in the ongoing investigation.

But some legal observers say recent developments in the Caso and Grimes cases suggest that the Weldons and Sexton may be in the clear.

Caso was scheduled to appear yesterday in U.S. District Court in Washington, D.C., for a status hearing. But on Tuesday, prosecutors filed a motion to cancel that hearing and set a May sentencing date.

"Although the investigation is not closed, the government will shortly be in a position in which it can describe the defendant's cooperation to the court and the impact that it should have on the defendant's sentence," Assistant U.S. Attorney Howard Sklamberg wrote of Caso, who was expected to testify against his former boss if any future charges were filed.

Sklamberg is making the same moves in the Grimes case. The day before her Jan. 23 status hearing, he filed a motion asking that the judge instead set an April sentencing date.

"The defendant's cooperation with the government is drawing to a close and the parties are ready to proceed to sentencing," Sklamberg wrote of Grimes, a close friend of Weldon's.

Cooperating witnesses who strike plea deals are typically not sentenced until after they testify against whomever the government plans to target, according to John Lauro, a defense attorney and former Assistant U.S. Attorney in New York.

"You want to keep that issue open and give the sentencing judge the ability to see the extent of the cooperation, which may have included testifying," Lauro said. The fact that prosecutors want to proceed to sentencing Caso and Grimes "signals to me that charges against anybody else are unlikely," he said.

Spokespeople for the U.S. Attorney's Office for the District of Columbia, the Department of Justice and the FBI declined to comment yesterday on the ongoing cases or the status of the corruption investigation.

Sexton's attorney, Joseph Fioravanti, said that there has been "no activity" in the investigation involving his client that he is aware of, while lawyers for Curt and Karen Weldon and Grimes declined to comment. Caso's attorney, Kelly Kramer, could not be reached.

Lawyers familiar with federal criminal procedure say it is unlikely that Caso or Grimes would be sentenced prior to a trial in which they are expected to testify. Prosecutors typically use the likelihood of a reduced sentence as an incentive for a cooperating witness to testify truthfully.

But other legal observers, including Peter Tague, a professor at Georgetown University School of Law, warned against reading too much into the government's recent actions. Tague, who specializes in criminal procedure, said it's possible that the investigation is winding down, but that it would be premature to assume that the Weldons and Sexton are in the clear. *