Jefferson was indicted a day earlier on 16 counts for alleged bribery and misconduct in office.

Matheson's call came shortly after Republicans complained Democrats were being hypocritical in saying they are running a more ethical Congress than when the GOP was in charge. Republicans also called Tuesday for Jefferson's expulsion from Congress.

After an exhaustive two-year investigation, the U.S. Justice Department received an indictment Monday alleging Jefferson used his official role to seek bribes from businesses trying to break into markets in the United States and Africa. The charges include solicitation of bribes, wire fraud, money laundering, obstruction of justice, conspiracy and racketeering.

In one case, FBI agents found $90,000 in cash sealed in frozen food containers in Jefferson's freezer, the agency says.

Matheson said Tuesday he was unaware of other Democrats calling for an investigation. Regardless, he said that since the indictment has been filed, it should be mandatory that the Ethics Committee "immediately" launch a probe into whether Jefferson broke House ethics rules. If he did, "he should be accountable."

"There should be zero tolerance for any proven violation of the public trust by elected officials here," Matheson said.

Jefferson remains in office, though on Tuesday he stepped down from his sole committee assignment.

National Republican Congressional Committee press secretary Ken Spain said Matheson should have spoken up earlier.

"Congressman Matheson stood silent when the Democratic caucus voted unanimously behind closed doors to place Jefferson on the Homeland Security Committee earlier this year," Spain said. (That role was never formally accepted on the House floor.)

"Now that he sees the political winds are shifting, he has decided to speak out," Spain added.

tburr@sltrib.com