A federal grand jury on Monday indicted Louisiana Democratic Rep. William Jefferson on 16 charges relating to a long-running investigation into bribery, racketeering, obstruction of justice and money laundering.

Calling it a "broad range of serious crimes," federal prosecutors called the case one about "greed, power and arrogance."

"The 16-count indictment alleges a pervasive pattern of self dealings, bribery and corruption by Mr. Jefferson, in violation of his oath of office, of his duty to the United States Congress in which he served, and of the duty to the citizens of the United States," said Chuck Rosenberg, the U.S. Attorney for the Eastern District of Virginia.

The officials said the investigation spanned from the United States to Africa and alleged it involved a number of occasions of criminal conduct by Jefferson, including bribing businessmen in a congressional building and promising a businessman that he would bribe a Nigerian official.

The chief prosecutor of the Justice Department's criminal division, Alice Fisher, said the case shows that the department is strongly pursuing corruption.

"Today's charges demonstrate that the Department of Justice will continue to enforce the public corruption laws that are designed to ensure the integrity of our government. The department will continue to hold accountable those public officials who will use their office and commit illegal acts such as the bribery schemes outlined in today's indictment," Fisher said.

The inch-thick, 94-page indictment was handed up in U.S. District Court in Alexandria, Va. If convicted on all charges, Jefferson could face a maximum prison term of 235 years.

Click here to read Rep. William Jefferson's indictment (pdf).

The high-profile case revolves around allegations that Jefferson used his political influence to gain leverage for himself and his family. He is accused of hiding $90,000 in cash in his freezer in 2005 and bribing Nigerian officials.

An FBI raid on Jefferson's Capitol Hill office last year became a constitutional showdown between Congress and the administration over whether the executive branch overstepped its boundary. The legality of the raid is still being argued on appeal.

Jefferson, 60, whose Louisiana district includes New Orleans, has said little about the case publicly but has maintained his innocence. He was re-elected last year despite the looming investigation.

Jefferson, in Louisiana on Monday, could not immediately be reached for comment, but his attorney spoke to reporters in Los Angeles.

"Congressman Jefferson is innocent. He plans to fight this indictment and clear his name," Jefferson Attorney Robert Trout said. Trout slammed the Justice Department for splashing news of the allegations of Monday's indictments and earlier leaks before trying the case in court, calling it an effort to sway public opinion.

Trout said that prosecutors have hounded Jefferson and his family, and lured the congressman into Virginia "so that they could secretly videotape him," but noted that the indictment doesn't say Jefferson promised any legislation, appropriations, earmarks or contracts.

"He's confident that when the facts are known, he will be vindicated," Trout said. "They picked the wrong congressman, and they picked the wrong facts."

Hearing of the indictment, House Minority Leader John Boehner, R-Ohio, announced he would offer a resolution to refer the indictment to the House ethics committee. The resolution, which could be voted on as early as Tuesday, will instruct the ethics panel to review the matter against Jefferson and report within 30 days on whether he should be expelled from the House.

Democrats will not oppose the resolution, a high-level Democratic aide told FOX News. Separately, House Speaker Nancy Pelosi called the charges "extremely serious."

"The charges in the indictment against Congressman Jefferson are extremely serious. While Mr. Jefferson, just as any other citizen, must be considered innocent until proven guilty, if these charges are proven true, they constitute an egregious and unacceptable abuse of public trust and power," Pelosi said in a statement.

Two of the congressman's associates who pleaded guilty and have been sentenced in the case agreed to work with investigators. One of those aides, Brett Pfeffer, admitted soliciting bribes on Jefferson's behalf and was sentenced to eight years in prison.

The other, Louisville, Ky., telecommunications executive Vernon Jackson, pleaded guilty to paying between $400,000 and $1 million in bribes to Jefferson in exchange for his assistance securing business deals in Nigeria and other African nations. Jackson was sentenced to more than seven years in prison.

Both Pfeffer and Jackson agreed to cooperate in the case against Jefferson in exchanges for their pleas.

The impact of the case even has roiled presidential politics in Nigeria. According to court records, Jefferson told associates that he needed cash to pay bribes to the country's vice president, Atiku Abubakar.

Abubakar denied the allegations, which figured prominently in that country's presidential elections in April. Abubakar ran for the presidency and finished third.

In Lagos, Nigeria, Abubakar spokesman Garba Shehu said the former vice president "has always denied wrongdoing in the matter."

"He has only had official interaction with the congressman, who the vice president felt deserved a hearing because he was a ranking member of the U.S. Congress," Shehu said. "The vice president was in no way cited in this thing, so we feel vindicated."

Court records indicate that Jefferson was videotaped taking a $100,000 cash bribe from an FBI informant. Most of that money later turned up in a freezer in Jefferson's home.

The charges handed up Monday against Jefferson also include honest services wire fraud, violations of the Foreign Corrupt Practices Act and conspiracy.

Although the indictment will no doubt raise political pressures on him to step down, Jefferson does not face any official sanctions in Congress as a result of the indictment alone, according to House rules. But should he be convicted, Jefferson could face disciplinary action including being excluded from votes if he receives a prison sentence longer than two years.

FOX News' Ian McCaleb, Molly Hooper, Jim Mills and The Associated Press contributed to this report.