Authorities say a thief hacked into the petty cash account of New York City's Education Department and stole $640,000.
A report by the Special Commissioner of Investigation found that the theft occurred between October 2003 and February 2007.
Commissioner Richard Condon said it was hard to understand how the DOE had not spotted the years of activities "reflecting hundreds of thousands of public dollars spent to pay bills.''
The DOE said it put in place tight controls on its petty cash accounts once it was made aware of the theft.
Albert Attoh was sentenced last month to a year in prison and fined $275,000 for the thefts. Condon said Attoh allowed individuals to use the account in exchange for cash.