Michael Brown, a former D.C. Council member who pleaded guilty in June to accepting bribes, faces more jail time after prosecutors uncovered new evidence of campaign finance violations.

In a new plea deal signed today, Brown admitted accepting more than $100,000 in secret funding to support his campaign in 2008 for an at-large D.C. Council seat. Under the terms of the new plea agreement, Brown, who hasn’t been sentenced, faces up to 43 months in jail instead of the 37 months in the original deal.

According to a joint report filed today in the U.S. District Court for the District of Columbia, prosecutors uncovered the new evidence of campaign finance law violations after Brown pleaded guilty to the bribery charge last year.

When Brown pleaded guilty to bribery last year, he also admitted to campaign finance law violations in connection with his failed 2007 campaign for the Ward 4 city council seat. The deal signed today adds new details about a secret get-out-the-vote effort funded by an unnamed local business owner in support of Brown’s successful 2008 campaign for the at-large seat.

Brown’s attorney, Reid Weingarten of Steptoe & Johnson LLP, could not immediately be reached for comment. A spokesman for the U.S. attorney’s office declined to comment.

According to court documents, Brown first sought a donation from the unnamed local business owner during his campaign for the Ward 4 seat in 2007. He received $20,000 from that individual in his personal account and gave the money to his campaign. Brown classified the donation as a personal contribution in his campaign finance report.

Brown didn’t win the Ward 4 race and decided to run in 2008 for an at-large seat. When Brown encountered financial problems during that campaign, he again sought help from the unnamed business owner, who agreed to secretly provide more than $100,000 for get-out-the-vote efforts, according to the new information added to his plea agreement.

In November 2008, Brown won the at-large seat. He’s no longer on the council, having lost his re-election bid in January 2013.

In both campaigns, the owner of a local public relations firm, Eugenia Harris, facilitated the payments between the unnamed business owner and Brown, according to court documents. Harris previously pleaded guilty to funneling more than $650,000 to a shadow campaign in 2010 that was supporting Gray and then trying to hide it from investigators.

In June 2013, Brown admitted taking a $55,000 cash bribe from undercover FBI agents posing as officials from a company seeking help with government contracting.

Brown is the third former D.C. Council member to be charged in federal court since 2012 with criminal misconduct. Former council members Kwame Brown and Harry Thomas Jr. previously pleaded guilty in unrelated cases.

Federal prosecutors in Washington also have an ongoing investigation into the 2010 campaign of Mayor Vincent Gray (D). A major target in that probe has been Jeffrey Thompson, a prominent businessman in the District who’s being represented by Williams & Connolly. Thompson has been publicly tied to the $650,000 shadow campaign in 2010.

Brown will come back to court for a new plea hearing before U.S. District Chief Judge Richard Roberts. In January, Roberts notified the parties that he knew Brown through the Washington chapter of a professional fraternity, Sigma Pi Phi. In today’s filing, lawyers for both sides said they would not ask to have the case reassigned to another judge.

Contact Zoe Tillman at ztillman@alm.com. On Twitter: @zoetillman