As elected officials and voters were lining up on either side of a sticker-campaign showdown between state Sen. Dianne Wilkerson and Democratic nominee Sonia Chang-Diaz in the final days of the campaign, a game-changer exploded on Tuesday morning when the incumbent was arrested and charged with federal corruption and wire fraud.

U.S. Attorney Michael Sullivan said the results of an 18-month undercover investigation showed Wilkerson accepted $23,500 in bribes for help getting a liquor license for a Roxbury nightclub and pushed legislation benefiting developers of a state-owned parcel of land in Roxbury. Sullivan's office released a 32 page document detailing the case against Wilkerson, including still photos of her taking what prosecutors described as cash payments from undercover agents and stuffing the money into her bra.

If convicted, Wilkerson could face up to 20 years in prison, three years of supervised release, and a $250,000 fine on each of the charges. A probable cause hearing for Wilkerson was scheduled for Nov. 17.

Despite mentions in the affidavit by a Wilkerson "associate" of other named legislators, Sullivan told the Reporter that there was "no evidence to suggest any other members of the Legislature are complicit."

"The timing of the election was coincidental with the timing of the takedown," Sullivan added.

The charges came by way of a criminal complaint, and will be eventually presented to a grand jury, which could return an indictment, Sullivan said.

"Sen. Dianne Wilkerson is entitled to the presumption of innocence and she cannot be found guilty until guilt is proven beyond a reasonable doubt," Max Stern, Wilkerson's attorney, told reporters outside the Moakley Courthouse on Tuesday afternoon, after Wilkerson was released from jail on $50,000 bail.

The charges come on top of a slew of baggage the eight-term senator carries. In 1997, she was convicted of failing to file tax returns. She eventually violated the terms of her probation and served 30 days in a halfway house. She also has a history of violating state campaign finance laws.

"Despite the picture show that the U.S. attorney has chosen to show you just one week before the election, I'm sure you know there's a context to every one of those interactions you've been told about," Stern said. "There's something that happens before, there's something that happens after that has not been included in what you've been shown. You will learn that when there is a trial."

Wilkerson already faced a steep uphill climb on Election Day, with what is regarded by political observers as a sub-par political organization and without the support of political machines such as that of Mayor Thomas Menino, who supported her primary re-election bid last month. She and her supporters were banking on a high turnout expected by the potential for the country to elect the first African-American president, U.S. Sen. Barack Obama (D-Illinois).

Supporters, colleagues and others expressed shock and sadness at the charges.

"It's just a heart breaker," said Dorchester's Judy Meredith, a long-time supporter. "I saw her in the State House when she was wearing an ankle bracelet, but this, she's just got to take care of herself. It's just a tragedy. She's been a great woman and a great leader. We've lost a champion."

"A lot of her issues up to now really struck me as sloppiness. She's never been vigilant in her own personal affairs," said Dorchester's Jim Keefe of Trinity Financial, a past Wilkerson supporter. "But I never would have suspected that she's been involved in this. It's sad. This goes beyond day-to-day issues. There are some really deep problems that she obviously hasn't been able to deal with."

"We have to worry about it if we're the constituents," said Amir "MC Spice" Shakir, a former DJ on TOUCH FM in Grove Hall who is a Chang-Diaz supporter. "Everyone who put a dime into the Wilkerson campaign, they would have never done any of that if they had known about this, and for small business owners that puts a financial strain on resources. She may try to pass the bag again but if I were her I would just concede and allow the legal process to take its course."

The Bay State Banner, the city's African-American newspaper which had editorialized in favor of Wilkerson's write-in bid to retain her seat on Nov. 4, withdrew its support for her in an editorial on Wednesday.

"It is evident that Wilkerson has breached the public trust. Consequently, the Banner can no longer support Wilkerson for public office," read the editorial.

State Sen. Jack Hart, a fellow Dorchester lawmaker, called the situation "tragic" and said his thoughts and prayers were with Wilkerson and her family.

"I think it's a tragedy all around," he said. "This is not a good day for her."

Hart said Wilkerson held "great promise" when she entered politics in 1992 and added that he had held "great admiration" for her. Hart said he had not seen the photos of her allegedly accepting the bribes.

A spokeswoman for Menino said the mayor felt Wilkerson had committed "an unacceptable breach of public trust" and felt "this type of behavior is absolutely unacceptable."

The City Council is mentioned throughout the criminal complaint.  In a statement, City Council President Maureen Feeney, a Dorchester Democrat, said she had met with officials from the Federal Bureau of Investigation and the Boston Police Department and pledged to provide "any and all information" to the ongoing investigation. "This is a disappointing day for all who are involved in public service. The people are right to expect a higher standard," she said.

In the complaint, Wilkerson is alleged to have delayed legislation in July 2007 originating from the City Council which would have eliminated a preliminary election for City Council seats, in order to get a liquor license for Dejavu, the Roxbury nightclub proposed by the FBI's cooperating witness.

Wilkerson allegedly boasted about her efforts to undercover agents, saying that Feeney had reacted angrily to her use of political clout, according to the complaint.

On Tuesday, a furious Senate President Therese Murray immediately removed Wilkerson from her chairmanship of the Committee on State Administration and Regulatory Oversight, which oversees public bidding laws, lobbying reporting laws and public construction. Murray said she would file an order referring Wilkerson's case to the Senate Ethics Committee, and called a Senate caucus for today.

Murray, who had promoted Wilkerson's candidacy earlier in the primary and sided with Chang-Diaz afterwards, curtly told reporters she was "extremely disappointed" with Wilkerson and would not say or do anything to interfere with the investigation. Murray said she would work with law enforcement officials "as they move forward."

Material from State House News Service was used in this report.