Washington - A former aide to Republican Rep. John Doolittle is scheduled to enter a plea Monday on charges related to the Jack Abramoff influence-peddling scandal.

    Kevin Ring, a former legislative director for the northern California congressman, worked for Abramoff, a former lobbyist who wined and dined congressmen and White House officials at his Washington restaurant, Signatures.

    Ring's pending plea Monday afternoon in federal court signals that federal prosecutors have not completed their wide-ranging investigation into Abramoff's ties to Washington's political elite. At one point, half a dozen lawmakers, including Doolittle, were said to be under scrutiny in the case. So far, only former Republican Rep. Bob Ney of Ohio has been convicted; he was released early from prison last month.

    Abramoff was sentenced Thursday to four years in prison for tax evasion, fraud, and conspiracy to bribe public officials in connection with defrauding casino-rich Indian tribes and encouraging former congressional staffers to violate a one-year lobbying ban.

    Ring's legal troubles also raise the stakes for Doolittle, who said in May 2007 that he had turned down an offer by prosecutors to plead guilty because he had not done anything wrong. Earlier this year, Doolittle announced that he would be stepping down at the end of his term.

    Ring's attorney, Richard A. Hibey, did not immediately return calls, but an assistant said he would be putting out a statement later today. According to a court administrator, Ring was scheduled to make an initial court appearance Monday afternoon.

    Ring, who worked five years for Doolittle before leaving his office in 1998, began lobbying his former boss when he went to work for Abramoff in 2000. Ring resigned from Abramoff's former lobbying firm, Greenberg Traurig, in 2004.