The House Democratic leader Thursday asked for an investigation of alleged threatening remarks made to the ethics committee chairman by GOP lawmakers.

Minority Leader Nancy Pelosi (search), in a letter to Speaker Dennis Hastert, asked the House ethics committee to investigate the comments allegedly made to its chairman, Joel Hefley (search), R-Colo. The comments apparently followed release of a report last week that criticized the conduct of Majority Leader Tom DeLay (search), R-Texas.

The Capitol newspaper The Hill quoted Hefley as saying: "I've been attacked; I've been threatened" by Republican lawmakers. The newspaper did not say who made the remarks, but Hefley separately told reporters he was not threatened by GOP leaders.

Pelosi wrote the speaker, "To uphold the integrity of the ethics process, I ask you to join with me in asking the committee to empanel an investigative subcommittee to immediately investigate Mr. Hefley's allegation."

Hefley has said in private conversations after the remarks were published that he didn't recall using the word "threatened," according to a House source who spoke with Hefley but would speak only if not identified.

Hastert spokesman John Feehery had no comment on the letter.

The ethics committee admonished DeLay's conduct in two separate reports in recent weeks.

The most recent report concluded that DeLay appeared to link political donations to a legislative favor and improperly persuaded U.S. aviation authorities to intervene in a Texas political dispute.

Earlier, the committee found DeLay tried to persuade Rep. Nick Smith (search), R-Mich., to vote for a Medicare prescription drug benefit — in return for DeLay supporting the House candidacy of Smith's son.