RALEIGH - Plenty of clues point to state House Speaker Jim Black as the pancake-house mystery man who gave former Republican Rep. Michael Decker a major infusion of cash in exchange for helping Democrats stay in power.

Decker's plea agreement Tuesday on a corruption charge answered some questions about why a Jesse Helms-style conservative would enrage fellow Republicans to help Democrats retain control of the state House in 2003. But it also raised one: Who was the unidentified House Democrat who prosecutors said gave Decker $50,000 for his switch?

The plea agreement and the unanswered question sent political tremors through Raleigh. Republicans began considering how to use the corruption issue in the November elections, and Democrats wondered whether the months of investigations, hearings and indictments involving political fundraising practices would ever end.

A somber Decker declined to talk to reporters as he left the federal courthouse in Raleigh. Black denied he had offered anything in exchange for Decker's vote.

But Decker's lawyer, David Freedman of Winston-Salem, said the $50,000 deal was made at a Salisbury IHOP, a location midway between their districts. And, while not confirming that Black was the mystery man, he noted a Winston-Salem Journal report in March that Black and Decker made the deal for Decker's vote at the restaurant just off Interstate 85.

Other evidence points to Black as well.

Tuesday's plea agreement said that Decker's campaign received four checks totaling $2,500 on the day he switched, and the checks were sent from Raleigh through a delivery service.

On that day, Black received via Federal Express four campaign checks totaling $2,500 made out to Decker, according to evidence from an earlier State Board of Elections hearing. Lobbyist Alexander "Sandy" Sands, who works in the Raleigh office of the Womble Carlyle Sandridge & Rice law firm, sent the checks from lawyers in the firm, and Sands testified that Black asked him to raise the money.

GOP sees an issue

If Black is indeed the mystery man, he could be the target of federal prosecutors. The speakership is one of the most powerful positions in state government; the speaker oversees the flow of legislation, the appointment of committees and even the assignment of offices and parking spaces. Black has tied the record as the longest-serving speaker.

Decker has agreed to testify in federal court about what he knows about the deal and about the unidentified Democrat, Freedman said.

North Carolina Republicans want to win back the House in November by portraying the Democrats as scandal-ridden, and thoughts of the influential four-term speaker in legal trouble have raised their hopes. The Democrats hold a 63-57 margin.

"I'm in a situation where we have seen one shoe drop, and shortly we will see some other shoes drop," said Ferrell Blount, the state GOP chairman from Pitt County.

Republicans already have been making political capital out of investigations surrounding Black's aggressive political fundraising from optometrists, video poker operators and others.

Black was even an important issue in the May Republican primaries, helping defeat GOP Rep. Richard Morgan of Moore County, who was criticized by some Republicans for agreeing to be co-speaker with Black in 2003.

Art Pope, a Republican businessman from Raleigh, said the Decker plea would have ripple effects as voters ask Democrats why they rallied behind Black this year. A political committee that Pope financed paid for primary election mailings connecting some Republicans to Black.

"There was a bagman bringing cash and checks to keep a losing Democrat in power," Pope said. "I think that's going to have a statewide impact."

Democrats hoped that this year's productive short legislative session -- including a package of good-government reforms -- would put the Black controversies behind them.

Just last week, Black said he would work hard to win re-election but was confident voters would return him to office.

"I do not believe they're going to throw out the speaker of the House and send a freshman down here," Black said Friday morning after the legislative session ended.

But Hal Jordan, a Charlotte Republican challenging Black in the district election, said Tuesday that his chances of victory improved with Decker's guilty plea.

"Any time ethics are brought up, it enhances my chances," said Jordan, a 47-year-old software sales representative.

It's too soon to say how Decker's disclosure that he took money to switch parties will play into the local campaign, Jordan said.

"I can't accuse him of anything," Jordan said of Black. "I think everybody suspects it was Speaker Black or somebody who was a surrogate of Speaker Black."

Democrats' worries

The Democrats kept the collective stiff upper lip they have maintained throughout their ordeal.

"It's of course highly distressing that any House member would take money for actions," said House Majority Leader Joe Hackney of Chapel Hill.

Was he worried about the political fallout?

"There has been worry all along," Hackney said. "So, yes, of course."

One person who said he took no delight in Decker's demise was Rep. Leo Daughtry, a Smithfield Republican. Daughtry thought he would be elected House speaker after Republicans won a 61-59 majority in the 2002 election. But Decker, a strongly conservative lawmaker from Forsyth County who felt neglected by the GOP majority, switched his vote and agreed to back Black. After being deadlocked in a 60-60 tie for several days, the House agreed on a co-speakership with Black and Morgan.

"It's a bad thing for the institution," Daughtry said of the Decker disclosures. "It's depressing to me."

Decker's plea bargain was another reminder that many investigators still are looking into the speaker's dealings. On Tuesday, several rows of the courtroom were filled by federal prosecutors and investigators, State Bureau of Investigation personnel and Internal Revenue Service agents.

(Staff writer Dan Kane contributed to this report.)