SOON AFTER a felony charge was filed against the brother of former D.C. Council chairman Kwame R. Brown, his attorney released a statement that amounted to a thumb in the eye to federal prosecutors.

“My client Che Brown was charged with bank fraud — not campaign finance fraud or theft or anything remotely related to his role in his brother’s political campaign,” said A. Scott Bolden in reporting Mr. Brown will plead guilty “not to political corruption, but to his personal mistakes.”

There was no immediate reaction from prosecutors. U.S. Attorney Ronald C. Machen Jr.’s practice has been to withhold comment until a guilty plea has been entered, but we trust he will be more forthcoming with information after Mr. Brown’s hearing Thursday. The biggest question is why the probe seems to be ending without producing solid answers to the troubling questions about Kwame Brown’s 2008 campaign finances that gave rise to the investigation more than a year ago.

We are not second-guessing the decision to bring the unrelated bank fraud charges against the two men and to insist on Kwame Brown’s resignation as chairman. Providing intentionally false information to banks is a serious offense, and, no matter how it was discovered, authorities had no choice but to prosecute it. That the city’s second-highest elected official should be mindful of the law is obvious. Moreover, lest anyone forget, it was Kwame Brown himself who invited investigation by the U.S. attorney. Faced with findings by campaign finance officials of numerous and serious violations of campaign finance laws, Mr. Brown asked the Board of Elections and Ethics in July 2011 to defer action (likely stiff fines and the attendant bad publicity) and instead refer the matter to federal prosecutors.

Kwame Brown had raised $825,000 in his largely uncontested race for reelection in 2008 as an at-large council member. An investigation by campaign officials revealed widespread discrepancies and irregularities. The raising and spending of more than $270,000 was not reported, and $239,000 was routed through one company before ending up at a firm run by Che Brown. Mr. Bolden told us that the money “absolutely” was used for campaign expenses but that there were issues with documentation since cash was involved. He said the government was provided with information — letters from vendors and a forensic reconstruction — to support the expenditures.

We hope Mr. Machen will detail what investigators learned about the activities of this campaign. How was this money raised and spent? What happens to the violations of campaign finance rules that had been documented by auditors in the campaign finance office? Kwame Brown is out of office, and this election is long past, but questions about the integrity of the process — and the adequacy of city laws and enforcement — are too critical to remain unanswered.