Of all real estate tax refunds issued in [the past 3 years], about half appeared suspicious.So this is an anticipated consequence. Controls of some sort should have been in place to prevent it. Indeed, a controller (sometimes comptroller) is "An officer who audits accounts and supervises the financial affairs of a corporation or of a governmental body."  When mechanisms to release resources are installed in the world, controls are needed to ensure that they are not released in unintended ways. It's the controller's job to ensure that improper use of resources is prevented. In this case, the Washington D.C. controller's office and the controls that were in place failed to do their job.
And of the $37 million refunded from the start of 2005 to July 2007, the dubious checks total more than $19 million.
Harriette Walters, the former manager in charge of property tax refunds, was arrested Nov. 7 and is charged with signing off on payments to sham companies controlled by family members and others who were in on the scheme. Six people have been charged, including tax employee Diane Gustus, one of several city workers who prepared or handled paperwork leading to the checks.
So far, prosecutors have publicly accused Walters and others of conspiring to fabricate 58 fraudulent refund checks, amounting to $20 million, and then using the sham companies to steer money to themselves. In court papers yesterday, prosecutors said that Walters has "confessed" to the activities and that she "approved each and every fraudulent voucher." …
[I]nvestigators aren't limiting their probe to Walters and the people now charged. Indeed, authorities said yesterday, one key concern is that Walters was not the first employee in the D.C. tax office to invent the refund scheme and may have been copying a scheme started earlier.