Disgraced former lobbyist Jack Abramoff may one day see an end to the scandal that he largely created — at least in his scheduled release from prison in late 2011 — but the complex criminal investigation spurred by his activities shows no signs of winding down anytime soon.

Among the 18 individuals charged with wrongdoing in the investigation that began in 2005, nine, including Abramoff, have been fined, sentenced to prison terms, placed on probation or some combination thereof.

On Friday, the Justice Department filed an indictment against Fraser Verrusio, a former aide to the Transportation and Infrastructure Committee, for accepting illegal gifts from Abramoff’s group while he was working for then-Chairman Don Young (R-Alaska).

But another seven individuals who pleaded guilty to a variety of corruption charges have yet to be sentenced owing to their on-going cooperation with Justice Department prosecutors.

On Tuesday, former Senate aide Ann Copland is expected to join this list and plead guilty to one count of honest services wire fraud in the U.S. District Court for the District of Columbia.

Among those who have agreed to cooperate with the Justice Department, the apparent efforts of Michael Scanlon, a former spokesman for ex-Rep. Tom DeLay (R-Texas), span the longest period, since he accepted guilt in a November 2005 plea that included conspiracy to commit bribery and honest services fraud. Scanlon colluded with Abramoff to over-bill Indian tribes.

Others who have staved off prison terms or other punishment include former DeLay aide Tony Rudy, who left the Hill to become a lobbyist with Abramoff, then ultimately pleaded guilty in March 2006 to conspiracy to commit honest services fraud, as well as mail and wire fraud and violating post-employment restrictions in the House.

Court appearances for Scanlon and Rudy have been repeatedly delayed at the request of their attorneys and the government, as both sides seek more time for the investigation.

“As part of his plea agreement, Mr. Rudy has agreed to cooperate with the government in any and all matters when required,— a recent joint filing in Rudy’s case states. “In conformity with this agreement, Mr. Rudy has been cooperating with government agents and prosecutors. The government anticipates that Mr. Rudy’s cooperation will continue for the foreseeable future. In the view of both parties, no issues have arisen which require the Court’s intervention at this time.—

Under the most recent court mandates, Rudy would appear in federal court March 26 and Scanlon in early May, but given previous court filings, those appointments are likely to be deferred within days of the scheduled dates.

Stan Brand, a one-time House general counsel and now white-collar defense attorney who is not associated with the Abramoff case, said although many months have elapsed since both men admitted their guilt, the timeline is not unusual.

“It’s pretty typical,— Brand said. “The government doesn’t want to allocute its sentencing until they know what the level of cooperation has been and how to measure it.—

A Justice Department spokeswoman declined to comment on the investigation.

But prosecutors likely do face pressure to complete their work.

“There are statute-of-limitations issues. There are staleness issues,— Brand said. “Evidence doesn’t usually age like wine; it gets worse as time goes by.—

In the meantime, former House aides Mark Zachares and John Albaugh also remain free as they continue to cooperate with investigators.

It has been nearly two years since Zachares, a former Transportation and Infrastructure Committee aide, admitted to accepting cash and favors from Abramoff in exchange for assisting the lobbyist’s clients. His is currently scheduled to appear in court March 26.

Similarly, Albaugh, who served as chief of staff to then-Rep. Ernest Istook (R-Okla.), pleaded guilty to conspiracy to commit honest services fraud in June 2008 and is currently scheduled to appear in court in mid-April.

The most recent wave of guilty pleas began in late October, when the Justice Department won an admission of guilt from former Senate aide Trevor Blackann.

Blackann pleaded guilty to a related charge of tax fraud for not reporting gifts — including a 2003 trip to the World Series in New York — that he received from “Team Abramoff— lobbyists Todd Boulanger and James Hirni.

Verrusio is charged with taking that same trip, which the government alleges was given to him because of his assistance in getting provisions into the highway bill for one of Abramoff’s clients.

Hirni and Boulanger pleaded guilty in subsequent hearings in December and January, respectively, to related charges of conspiracy to defraud the government.

Hirni, Boulanger and Blackann have agreed to cooperate with federal investigators. An initial status hearing in Blackann’s case set for mid-February was postponed until May.

Copland, a longtime aide to Sen. Thad Cochran (R-Miss.) who left the Hill in 2008 to join Mississippi Public Broadcasting, is scheduled to appear in court Tuesday, where she is expected to accept a guilty plea for honest services fraud.

According to court documents, Copland accepted more than $25,000 in concert and sporting event tickets from Abramoff and his associates between 2002 and 2004.

While Sen. Judd Gregg (R-N.H.) has acknowledged that his one-time legislative director, Kevin Koonce, is also under investigation for allegedly accepting more than $10,00 in gifts from Abramoff’s team between 2002 and 2004, Koonce has not been charged.

In the meantime, Kevin Ring, who was an aide to then-Rep. John Doolittle (R-Calif.) and later joined Abramoff as a lobbyist, is one of only two individuals named in the Abramoff investigation who has opted to challenge the Justice Department.

Attorneys for Ring, who is scheduled to go on trial in September, filed a motion in January to dismiss the government’s indictment, asserting he did not violate any laws in existence at the time of the allegations.

“The Department of Justice has repeatedly decried the reach of federal anti-corruption laws, particularly as construed by the Supreme Court, and actively lobbied the Congress to broaden those laws. To date, those efforts have failed,— Ring’s attorney Richard Hibey wrote in court documents. “Despite that failure, the government has secured an indictment against Kevin Ring that reflects the law as the government wishes it were, not as the law actually existed at the time of the charged offenses.—

In the only other trial to occur to date, a jury convicted former White House official David Safavian of lying to ethics officials about his relationship with Abramoff. Safavian was convicted on similar charges in 2006, but that verdict was overturned.

Paul Singer contributed to this report.