WASHINGTON (CNN) -- The first ad of the 2008 Congressional campaign season questions the ethics of a New Mexico congresswoman and her role in the controversy over the firings of eight U.S. attorneys.

The radio ad, paid for by the Democratic Congressional Campaign Committee (DCCC), begins airing Wednesday.(Listen to ad via DCCC's website)

It uses testimony from one of those fired attorneys -- David Iglesias of New Mexico -- before the Senate Judiciary Committee in which he says Rep. Heather Wilson, R-N.M., called him to inquire about a federal corruption investigation he was heading.

"She said 'What can you tell me about sealed indictments?' The second she said any questions about sealed indictments, red flags went up in my head, because as you know, we cannot talk about indictments until they're made public, in general, we specifically cannot talk about a sealed indictment," Iglesias testified.

"A phone call is made ... a scandal begins," the ad's narrator says. "Serious questions remain about Heather Wilson and violation of congressional ethics rules. It's time for Heather Wilson to release her phone records and come clean," the narrator says in the ad.

Iglesias is one of eight U.S. attorneys who were fired in the past several months -- for performance and managerial issues, said the Justice Department.

But some Congressional Democrats are questioning if politics were in play in the dismissals. Republicans in the Senate have been accusing Democrats -- especially
Democratic Senatorial Campaign Committee Chairman (DSCC) Sen. Chuck Schumer -- of politicizing the prosecutors issue. But DCCC spokeswoman Jennifer Crider suggested the congresswoman herself made public corruption a key issue in her campaign.(Watch Video: Sen. Arlen Specter says Schumer is exploiting the firings for political gain)

Wilson is one of the most vulnerable Republicans in Congress, after only
narrowly winning in the past two elections. In 2006, the former Air Force officer ran against New Mexico Attorney General Patricia Madrid and make corruption a big issue as Democrats in that state were being investigated in kickback schemes. Madrid lost to Wilson by approximately 800 votes.

Related video: CNN's John Roberts reports on Bush's refusal to let his staff testify publicly on the controversy

Related video: CNN's Dana Bash reports that a showdown in Congress is brewing over firings