When an aide to Rep. Jesse Jackson Jr. (D-Ill.) this week revealed the Illinois lawmaker to be an FBI informant, it put Jackson in an unusual and potentially uncomfortable position among his Congressional colleagues.

By all accounts, few lawmakers are publicly known to have assisted federal investigators aiming to convict a fellow political officeholder — and those who have are often facing legal challenges of their own.

“Turning a politician against another politician is not something that happens every day,” said defense attorney and former House general counsel Stan Brand. “You don’t advance your career and your trust with other elected officials when you do that.”

Indeed, Jackson, who has sought to distance himself from the corruption scandal involving Illinois Gov. Rod Blagojevich (D), has said he is not under investigation by the FBI and has denied any wrongdoing in Blagojevich’s alleged scheme to auction off the state’s open Senate seat.

A Jackson spokesman told the Associated Press on Tuesday that the Illinois lawmaker has fed information to federal investigators working on the case for years.

The Jackson aide, Kenneth Edmonds, reported that the Congressman had discussed Blagojevich as well as unidentified “others.”

A Justice Department spokesman in Chicago, assistant U.S. attorney Randall Samborn, declined to confirm or deny Jackson’s involvement with investigators, stating he could not comment on the assertions.

FBI spokesman William Carter declined to discuss whether or how often Members serve as informants or otherwise assist with investigations, noting: “It’s like sources for a reporter.”

“We don’t usually talk about individuals who are cooperating with the FBI,” he said.

Similarly, those Members who have assisted federal investigators are unlikely to reveal it, Brand said.

“That would be an uncomfortable conversation,” Brand said. “It’s not something likely to be shared with your colleagues.”

Brand, who served as House general counsel during the ABSCAM scandal in the late 1970s and early 1980s, recalled government investigators made some efforts to turn Members in the case, but they ultimately relied heavily on videotaped incidents of lawmakers seeking or accepting bribes.

Federal prosecutors did, however, call Rep. John Murtha (D-Pa.), an unindicted co-conspirator in the case, to the witness stand to testify against then-Reps. Frank Thompson (D-N.J.) and John Murphy (D-N.Y.).

Congressional aides and House officers have also at times acknowledged their assistance to federal prosecutors targeting Members.

During the House Post Office scandal in the early 1990s, then-House Postmaster Robert Rota resigned and assisted federal prosecutors in identifying Reps. Joseph Kolter (D-Pa.) and Dan Rostenkowski (D-Ill.). Both lawmakers ultimately pleaded guilty to related charges.

More recently, Will Heaton, chief of staff to then-Rep. Bob Ney (R-Ohio), actively assisted federal prosecutors by secretly taping conversations with the Ohio lawmaker, who ultimately pleaded guilty to two federal corruption charges, including conspiracy and making false statements. Ney was sentenced to a 30-month prison term but was released early in August.