VINCENT B. ORANGE, an at-large member of the D.C. Council, acknowledged Monday that donations made to his campaign in last year’s special election are questionable and require further investigation. “My examination of the money orders leads me to believe that they are suspicious and questionable as to who actually paid for the money orders,” Mr. Orange (D) wrote in a statement to us. The city’s Office of Campaign Finance, he added, “should examine the money orders to determine if they are legal or illegal.”

Mr. Orange initially brushed off questions about money orders donated to his 2011 special-election campaign as a political ploy by opponents seeking to unseat him in the April 3 Democratic primary. So we are glad he is finally considering seriously whether the money orders were a shield for straw-man donations to elude legal giving limits. In addition to calling for further investigation, he promised to refund any “illegal, suspicious or questionable” donations.

The money orders became an issue after WAMU reporter Patrick Madden traced some of the contributions to prominent businessman Jeffrey E. Thompson, whose home and offices were recently raided by federal agents. The U.S. Attorney’s Office is conducting multiple investigations into possible corruption; among those believed to be under scrutiny are Mayor Vincent C. Gray (D) and D.C. Council Chairman Kwame R. Brown (D).

Mr. Orange stressed in his statement that his campaign had properly reported the donations and had cooperated with the campaign finance office when it requested information about some of the donations. But most people who give $500 or $1,000 do so by check or credit card, so such money orders in themselves should raise a red flag. According to Mr. Orange, his examination revealed 19 money orders in the amount of $1,000 and 14 in the amount of $500. Some checks, ostensibly from different donors, have seemingly identical signatures. Sequential serial numbers on others suggest purchases made at a single time and place, possible signs that the orders were used to shield straw-man donations.

Why Mr. Orange, who is both an accountant and lawyer, didn’t realize earlier that there might be a problem is one of the questions that should be asked. He showed us copies of some of the money orders Monday; he should release them all. And voters might also wonder why the District, which places a $25 cap on cash contributions, allows the use of money orders at all.