Howard Brooks, a key campaign worker for Mayor Gray's 2010 campaign, leaves the E. Barrett Prettyman United States Court House after entering a guilty plea in a hearing on the charge of making a false statement to FBI agents. (Jahi Chikwendiu/WASHINGTON POST)

A former aide to Mayor Vincent C. Gray’s 2010 campaign should be sentenced to probation, not jail, because he “took full responsibility for his crimes and provided substantial assistance” to authorities, federal prosecutors wrote in court papers filed Monday.

Howard Brooks, 64, pleaded guilty in May to one felony charge of making a false statement to FBI agents about helping to funnel illicit payments to the campaign of a fringe mayoral candidate and to Gray’s own election effort. Under federal guidelines, he faces up to six months in jail at his sentencing Oct. 10 before U.S. District Judge Colleen Kollar-Kottelly.

In court papers, prosecutors called Brooks’s conduct “quite serious,” adding that it “caused significant damage to the image and integrity of the District’s electoral process.”

Nevertheless, they wrote, Brooks offered them so much help that he should be spared jail. “Based on the extent of his cooperation,” they wrote, “he appears to be truly ashamed of his conduct and desirous of righting the wrongs that he has committed.”

Federal prosecutors did not disclose the nature of Brooks’s “substantial assistance.” But sources have said that he wore a recording device that captured another campaign aide on tape admitting he destroyed a key ledger of illegal payments.

Bill Miller, a spokesman for the U.S. attorney’s office, declined to comment.

Brooks’s attorney, Glenn F. Ivey, also declined to comment. But he argued in court papers for a sentence of probation, writing that Brooks knows he did something wrong and cooperated with authorities to make things right.

Brooks was on the finance and treasury teams of Gray’s 2010 campaign for mayor. At the time, Gray was the D.C. Council chairman and was engaged in a fierce election battle with then-Mayor Adrian M. Fenty in the Democratic primary. Gray beat Fenty and cruised to a general election victory.

But shortly after Gray took office, a fringe candidate alleged that he had accepted money and a job offer in Gray's administration in return for staying in the race to assail Fenty. Brooks later admitted in the District’s federal court that he had diverted $2,810 in Gray campaign funds to that candidate, Sulaimon Brown, through hard-to-trace money orders. He also admitted that he provided $2,000 in straw donations to Gray’s campaign. He was the second Gray campaign staffer to plead guilty to a federal charge related to illicit campaign payments. Thomas W. Gore, 56, admitted that he obstructed justice by shredding a notebook containing records of payments to Brown and that he violated some D.C. campaign finance misdemeanors.

Mike DeBonis and Nikita Stewart contributed to this report.