Rep. Charles Rangel (D-N.Y.) on Wednesday will formally ask the House ethics committee to investigate allegations that he misused his congressional office.

Aides to the powerful chairman of the Ways and Means Committee were putting finishing touches on the letter Tuesday night, according to Rangel spokesman Emile Milne.

[Editor's note: The text of Rangel's letter to the panel and accompanying documents can be viewed here .] 

House rules require the ethics committee to initiate an investigation if a sitting House member files a formal complaint with the panel. Fearing political retribution, members rarely file complaints against each other, and ethics experts say they have never heard of a lawmaker filing a complaint against himself.

In an angry press conference last week, Rangel said he had asked staff how to write the complaint. He also attacked a Washington Post story about Rangel’s efforts to raise money for a New York City college center in Harlem bearing his name. The article alleged that Rangel had broken House ethics rules barring the use of congressional letterhead for financial solicitations.

Rangel said he didn’t believe he had violated any ethics rules and thought the ethics committee would agree with him. Speaker Nancy Pelosi (D-Calif.) last week said she supported his request for a probe.

Rangel said he would not ask the ethics committee to examine a separate issue raised in articles in The New York Times: Rangel’s use of four rent-controlled apartments (one of them as a campaign office) in Harlem’s Lenox Terrace building.

Most New York citizens are unable to have more than one rent-controlled apartment at a time, and the city’s regulations bar the use of rent-controlled apartments as office space. Rangel said he wouldn’t ask for an investigation but would give up the unit used as an office.

But Public Citizen’s Craig Holman said the ethics committee could investigate Rangel’s apartments if it chooses to because it has the power to expand any investigation beyond allegations in the official complaint. Holman said he believed Rangel had broken the House gift rule by having more than one rent-controlled apartment under his control, and the panel should examine it.

The last member to file an official ethics complaint was former Rep. Chris Bell (D-Texas), who in 2004 accused then-Majority Leader Tom DeLay (R-Texas) of bribery, laundering illegal corporate political donations and illegally using his congressional office to ask the Federal Aviation Administration for the location of Texas Democratic legislators who were absent from a session to protest a GOP redistricting plan DeLay spearheaded.