Staffers at the U.S. House of Representatives have repeatedly spent work hours tampering with the biographies of Rep. Richard Pombo, R-Tracy, and dozens of other lawmakers in the online encyclopedia Wikipedia, according to Wikipedia's founder.

On at least seven occasions between Oct. 5 and Jan. 26, someone using a Capitol Hill computer anonymously logged on to the popular reader-driven Web site and sanitized Pombo's biography.

Attributed references that connected Pombo to disgraced lobbyist Jack Abramoff or to fund-raising controversies disappeared from the Web site, which describes itself as the "free encyclopedia that anyone can edit."

Other information was added or deleted to present the congressman in a more favorable light, according to a survey of the changes.

All of the comments examined by The Daily Review can be traced to office computers belonging to the internal computer network of the U.S. Congress.

The entry on Pombo was one of hundreds of politically themed encyclopedia articles that were subject to editorial tampering by government employees.

Some of the Wikipedia changes were explicit, such as when someone used a House computer to describe Rep. Tom Coburn, an Oklahoma Republican, as a "huge deuche-bag (sic)."

Others were more subtle.

A staffer who works for Rep. Tom Lantos, D-San Mateo, admits that her office logged on to Wikipedia to report that her boss is an "ardent internationalist" who is friends with U.N. Secretary-General Kofi Annan.

Lynne Weil, communications director for Lantos, said all of the additions she made to Wikipedia were attributed to legitimate sources, such as local newspapers.

"The problem is, a lot of that information (on Wikipedia) isn't filtered for neutrality or truth as quickly as it's put up," Weil said. "I don't know what the solution is, because there are just so many people who can contribute to it that aren't held responsible."

Someone else using a congressional computer made changes to the entry on House Minority Leader Nancy Pelosi that described the San Francisco Democrat unfavorably.

A sentence describing Pelosi as representing her party's liberal wing was altered to say she is part of its "extreme" wing. Another edit stated that she "villifies" the same companies she raises money from.

Wikipedia founder Jimmy Wales said his widely read Internet resource relies on everybody who uses it to write, edit and monitor the accuracy of its articles. And so it is not surprising, he said, that politicians or their staffers or interns make so many contributions.

But he said some congressional workers "vandalized" the encyclopedia by adding libelous statements about their political opponents or anonymously removing unfavorable but verifiable information about the politicians they support.

"It's definitely a bipartisan scandal because there's enough idiocy to go around for everybody," Wales said.

Wales pointed out that most of the information that congressional staffers contributed was appropriate and not harmful. For instance, anyone who corrects factual errors on the Web site is making the encyclopedia a better resource, he said.

But he said contributors should sign their names when they make changes and not remove information attributed to a reliable source.

"If we're citing the press, they really shouldn't take that out," Wales said.

Pombo spokeswoman Nicole Philbin said Thursday she would look into whether any Pombo staffers made any changes to the congressman's Wikipedia biography.

However, she did not return repeated follow-up calls and did not respond to an e-mailed list of changes to the Pombo biography that was compiled by The Daily Review. Of lawmakers in Northern California who have biographies on Wikipedia, Pombo's was the one which had the most changes that can be traced to the House computer network.

Most of the information on Pombo that was deleted by congressional staffers is back on the Web site because other contributors edited the page again. 

And it is impossible, without the help of Capitol Hill's computer technicians, to determine precisely who edited any of the Wikipedia entries or pinpoint what office within the House of Representatives they came from.

Wikipedia records the Internet protocol number, known as the IP address, of everyone who contributes to the Web site's hundreds of thousands of entries.

A search through the American Registry for Internet Numbers, a nonprofit Virginia-based organization, confirms that changes examined by the Daily Review came from a House IP address.

Jon Brandt, spokesman for the Committee on House Administration, which oversees the congressional Web network, said he cannot reveal any information about the IP numbers of House offices because of potential threats to security.

"We do not provide information regarding specific IP addresses," Brandt said. "We don't provide that kind of information."

The widespread use of Wikipedia by congressional staffers was first disclosed on Jan. 27 by a report in The Sun, a newspaper in Lowell, Mass.

Staffers for U.S. Rep. Marty Meehan, D-Mass., admitted they deleted a truthful sentence from Meehan's profile, about a broken campaign promise, and replaced it with staff-written biographical information.

The story spread quickly over political Web logs and has renewed debate over the accuracy of the Wikipedia, a site many Internet users consider a serious resource. Last year a former Robert Kennedy aide sought to discredit the site when he found out someone wrote that he was "directly involved in the Kennedy assassinations."

Weil, the Lantos spokeswoman and an acknowledged fan of Wikipedia, said most of the problems on the Web site stem from anonymous users who pour venom into encyclopedia entries with offensive "drive-by" comments.

"There's been some real ugly drive-by, vicious, untrue defacement of the Wikipedia page about Tom Lantos," Weil said. "Whoever is doing it is abusing the privilege of contribution to a great resource."

Weil said that if she contributes to the Lantos section in the future, she will sign her name. She said she would have left her signature before but did not know how.

Wales said he hopes the knowledge that they are being watched by Wikipedia's many readers keeps legislative staffers in check in the future.

"It can be perfectly appropriate for people to enter the public dialogue," Wales said. "The real question is, you know, are people behaving in a mature, thoughtful manner?"