Federal prosecutors on Wednesday charged a second senior member of D.C. Mayor Vincent Gray's 2010 campaign with trying to cover up a plot intended to heighten Gray's chances of toppling a sitting mayor.

Howard Brooks, a consultant to the Gray campaign, was charged with making a false statement to the FBI because prosecutors say he lied when he told investigators he never delivered payments to a fringe mayoral candidate Sulaimon Brown or Brown's campaign.Those payments, which Brown publicly disclosed in March 2011 when he also alleged the Gray campaign had promised him a job in the Gray administration, prompted an expansive grand jury probe into Gray's campaign.In a charging document known as a criminal information -- a type of filing that signals a guilty plea is imminent -- prosecutors said Brooks "knowingly and willfully [made] a materially false, fictitious and fraudulent statement or representation."

Brooks is scheduled to appear Thursday before U.S. District Judge Colleen Kollar-Kotelly for a plea hearing on the charge, which carries a prison sentence of up to five years. Under federal sentencing guidelines, though, Brooks would likely receive a prison term of far less, if a judge ordered incarceration at all.

Brooks' attorney did not respond Wednesday to a request for comment.

After months of silence about their findings, prosecutors have sharply accelerated the probe's public pace recently, with Brooks being the second person in three days to face charges.

On Monday, the government charged Thomas Gore, the campaign's assistant treasurer, with a felony: obstructing justice. Prosecutors also charged Gore with three misdemeanor violations of District campaign finance law.

Gore pleaded guilty Tuesday, and, under his agreement with prosecutors, faces a prison term of 12 to 18 months on the obstruction charge alone. He could receive a more lenient sentence, though, if he provides "substantial assistance" to investigators.

At his plea hearing, Gore acknowledged he had helped direct contributions from the Gray war chest to Brown's campaign using the names of unknowing individuals.

Gore also admitted to shredding a spiral notebook that contained records of the transactions.

Although Gore played an integral role in carrying out the scheme, prosecutors said, he did not directly transmit the funds to Brown.That was allegedly the role of Brooks, previously identified in court filings only as "Person A."

Gore acknowledged that "Person A" had delivered five money orders to the Brown campaign in June and July 2010. The money orders, signed in the names of members of Brooks' family, totaled $660.

At the John A. Wilson Building on Wednesday, Gray declined to comment.

"There's an ongoing, pending investigation, so there's nothing really I can comment on," Gray said.

In a statement issued before Brooks was charged, Brown called on Gray to resign "immediately, if not sooner," saying the mayor had violated the public trust.