An employee of Chicago’s Field Museum stole $900,000 from the institution over the course of seven years, museum officials revealed on Friday with the publication of internal tax documents.

The scheme was allegedly carried out by a non-management employee who would pocket the money when museum visitors paid for an annual membership, which costs $85. She would create a temporary ID card, and enter the membership on the books, without entering the payment on the books.

“Yes, it’s embarrassing somebody got away with it for seven years,” Ray DeThorne, the Field Museum’s chief marketing officer, told the Chicago Tribune. “But we’ve made sure it won’t happen again.”

Lots of museum thefts are inside jobs, but usually the headlines are about objects stolen from the museum collection, like the Uzbek State Art Museum employees that replaced the museum’s artworks with forgeries, or the blatant thievery of the director and staff of Macedonia’s National Museum. Improper use of museum funds tends to be more sophisticated, like Dede Wilsey‘s contested disability severance package to the husband of a favored employee, or the suspected Ponzi scheme run by Gérard Lhéritier at Paris’s Musée des Lettres et Manuscrits.

The Field Museum theft was made public thanks to the museum’s tax report, filed this month. On its 2014 Form 990 (which has been published by the Tribune), the museum had to divulge if had become aware of any significant diversion of assets over the course of the year.

“The loss and investigation costs were fully recovered through the museum’s insurance program, less a $10,000 deductible,” the form noted, but the Tribune reports that the Field Museum has had to lay off employees in recent years as it has struggled to repay construction-related debts.

The Field Museum.
Photo: courtesy the Field Museum.

When the theft was discovered in April of 2014, “during a restructuring of longstanding museum departments and an internal review of finances,” according to an official statement, the employee was immediately terminated. The museum had not previously publicized the situation due to ongoing investigations on the part of the FBI and US attorney’s office, who are involved because the institution receives money through federal grants.

DeThorne told the Tribune that he did not know why charges had not yet been filed against the woman, who has not yet been identified. In response to the theft, the museum has added video surveillance at museum cash registers.

According to the tax filing, the museum received $2.8 million in museum membership fees in 2014. The institution reportedly has about 46,000 members.