The House ethics committee has begun an informal probe into whether Rep. John Conyers (D-Mich.) and his aides improperly conducted partisan political activities out of his Detroit office during 2002 and 2003, according to sources close to the committee.

This comes as Ray Plowden, the longtime head of Conyers’ district office, has quietly left the veteran Democrat’s staff and is working for a nonprofit organization in Detroit. Conyers is running the district office himself at this time, one aide said.

The Conyers investigation is one of four “informal” probes being undertaken currently by the ethics committee, said the sources. The others involve Reps. Curt Weldon (R-Pa.) and Karen McCarthy (D-Mo.) and were initiated by the committee on its own authority following news reports about the lawmakers. A fifth probe relating to Rep. Nick Smith (R-Mich.) is now a full-blown investigation, and an investigative subcommittee of the ethics panel has been appointed to look into this case.

The allegations regarding Conyers were first reported by the Detroit Free Press in late November. The newspaper stated that members of Conyers’ staff, including an employee of the House Judiciary Committee, engaged in partisan campaign activities on government time, and operated out of the 20-term lawmaker’s district office.

Over a two-year period, Conyers’ aides reportedly worked on Michigan Gov. Jennifer Granholm’s (D) 2002 gubernatorial campaign, a number of city and county races, a California ballot proposal to ban the collection of racial data, and the unsuccessful campaign of Conyers’ wife, Monica, for a state Senate seat.

The Free Press also reported that Conyers and his staff raised money, organized fundraisers and engaged in other campaign activities out of the Detroit office, and that there was no line between official government action and campaign activities.

According to House ethics rules, “House employees are free to engage in campaign activity, provided that they do so on their own time, outside of congressional space, and without use of any House resources.”

It is also illegal to solicit campaign contributions from any Congressional office or building.

Plowden and other Conyers aides denied the charges when the Detroit Free Press published its original story on Nov. 21, 2003. Conyers’ office did not return numerous calls seeking comment for this story.

Plowden, who along with Conyers was alleged to have ordered staffers to work on Monica Conyers’ campaign, took leave last year from the Michigan Democrat’s staff to help work on Rep. Richard Gephardt’s (D-Mo.) presidential campaign in the Wolverine State. Plowden, who was appointed district office director in 1995, now works for the Detroit chapter of pro-Democratic 527 organization called America Votes. Plowden did not return calls seeking comment.

Conyers was first elected to the House in 1964 after a stint working for Rep. John Dingell (D-Mich.) as a legislative assistant. Conyers now serves as the top Democrat on the House Judiciary Committee.

The 74-year-old Conyers twice ran for mayor of Detroit but fared poorly in both of those campaigns, although he remains influential in Motor City politics.

In a related matter, the head of a liberal government watchdog group wrote to Attorney General John Ashcroft on Wednesday seeking an investigation of Weldon for allegedly violating federal bribery statutes.

According to Melanie Sloan, executive director of Citizens for Responsibility and Ethics in Washington, Weldon may have “violated federal bribery law by using his public office to benefit companies that hired his daughter as a lobbyist.” Sloan is a former Conyers aide and an ex-federal prosecutor.

Karen Weldon is a lobbyist whose firm has signed up several foreign companies and clients since going into the lobbying business in September 2002. Her partner is Charles Sexton, the former finance director for several of Curt Weldon’s campaigns.

Her father had contacts with, or took actions on behalf of, those clients shortly before or after Karen Weldon’s firm had inked the deals with them, which included a $500,000-per-year agreement with a Russian natural gas firm to create “good public relations” for the company and a $240,000 contract to help win U.S. visas for members of a wealthy Serbian family linked to accused war criminal Slobodan Milosevic.

“Mr. Weldon’s activities on behalf of his daughter’s clients both shortly before or shortly after Ms. Weldon won contracts from those clients appear to violate the bribery laws. The clear inference to be drawn is that Karen Weldon was highly compensated in return for her father’s official assistance,” Sloan wrote.

Federal law prohibits a public official receiving anything of value personally or for any other person in return for undertaking an official act.

Rep. Weldon has strongly denied any suggestion of wrongdoing on behalf of his daughter, and has hired a top Washington ethics lawyer to handle his case.

But the House ethics committee has already begun an informal investigation into the allegations on its own authority, and it’s unclear what steps the panel will take next. Weldon and his lawyers have turned over hundreds of pages of documents to the ethics committee that justify his actions and rebut the charges of assisting his daughter’s company. The allegations about the Weldons were first reported by the Los Angeles Times.

No comment was available from Weldon’s office at press time.