Two men who stole $1.5 million from the Department of Education by billing for special education services they did not deliver had help from someone inside the department, according to a report released today by city investigators.

Here’s how we reported about the fraud in August, when Special Commissioner of Investigation Richard Condon announced the finding:

The fraud was apparently able to take place because of shortcomings in the Office of Non-Public Schools Payables, which pays independent vendors to provide services to students with disabilities that the department can’t otherwise offer.

Before it authorizes payments, the office first reviews a document — called a related service authorization form — that gives permission to parents to obtain services from an approved independent vendor. These forms included signatures from both parents and education department employees, which Ruiz and Cruz were forging.

Investigators found many of these forms were also outdated, contained wrong addresses, and were issued out of the wrong school district. But when office employees reviewed them, they didn’t pick up on the discrepancies.

Today, Condon’s office released a second report finding that it wasn’t lax oversight but outright fraud that got the bills paid. Since 2008, investigators found, a clerk in the office had taken $700 a month from the two fake special education vendors in exchange for processing their forms.

The clerk, Thomasina Chappell, confirmed the payments to investigators and resigned from the department last month. One of the two men who devised the scheme, Nelson Ruiz, disclosed that he had bribed a department official to certify his forms when he pled guilty to fraud earlier this week.