D.C. Councilman Michael Brown's re-election campaign did not report more than $8,000 in contributions and another $13,000 in expenses, an audit by city campaign finance regulators found.

The D.C. Office of Campaign Finance began the review after Brown said in June that someone had stolen a "significant" sum from his war chest and that he had fired his campaign treasurer. Earlier this month, Brown said nearly $114,000 was missing.

City auditors found that Brown's disclosure reports did not report nine donations worth $8,446.60 and said each "may represent individual violations" of city law.

The office also said Brown's campaign did not disclose $12,329.48 in expenditures and nearly $1,000 in bank charges.

Those unreported expenses, auditors said, were in addition to $113,950 in "unexplained expenditures" to Hakim Sutton, the enduring political operative whom Brown ousted as his campaign treasurer. The Metropolitan Police Department has said it is conducting a "very active" investigation of the reported theft, but no one has been charged.

Sutton's attorney has strenuously denied any wrongdoing, though Asher Corson, a Brown campaign spokesman, said Brown had corrected any problems that transpired during Sutton's tenure.

"Since taking over as treasurer, Michael Brown has corrected all the problems that occurred under the previous treasurer," Corson said.

The audit also detailed other troubles for Brown's campaign finances, including excessive contributions totaling $750 and donations and expenses that didn't go through the campaign's bank account.

The audit findings are the latest challenge for Brown, a self-styled "independent Democrat," as he seeks a second term as a city lawmaker.

A Sept. 10 campaign finance filing showed the unreported payouts linked to Sutton had run Brown's coffers to a low level for a citywide candidate. The campaign said in the disclosure that it had about $18,000 on hand, a figure that trailed two of Brown's rivals.

Also this month, the D.C. Board of Elections & Ethics invalidated more than 1,500 of the signatures that Brown used to qualify for the Nov. 6 ballot. Regulators ultimately said Brown had filed 3,166 valid signatures -- only 166 above the minimum to guarantee a spot on the ballot.

Brown has also faced questions about his driving record and his personal financial history, which includes tax liens and missed rent payments.

His opponents have pounced.

Mary Brooks Beatty, the Republican nominee for the at-large seat on the D.C. Council, last week launched a website demanding Brown's resignation. On Monday, Beatty said the new audit's findings weren't a surprise.

"This is just a lot more of the same," she said. "There are some additional facts that came out through the audit that concern me, but it's the same type of behavior we've seen before."

Brown's 2008 campaign also faced scrutiny from auditors. A 2009 city review found that Brown's campaign did not report about $122,000 in expenditures and bounced 49 checks.

The campaign also exceeded the $300 limit for checks made payable to "cash" on seven occasions, totaling $16,042.75.