He put his stamp on the U.S. Postal Service.

A manager at a New Orleans post office is accused of swiping nearly $630,000 in stamps in order to fund gambling excursions in what authorities said was the largest inside job in the agency's history.

Ryan S. Cortez, the manager of customer service operations at the North Kenner Post Office, was arrested Wednesday after a federal investigation and charged with misappropriation of Postal Service funds or property.

According to a criminal complaint affidavit, Cortez allegedly stole approximately $630,000 in U.S. stamps and sold them on eBay. The Attorney General's Office said it was the largest internal theft by an employee in the history of the U.S. Postal Service.

Postal agents with the Office of Inspector General were alerted to the potential crime by eBay and PayPal after the companies noticed that Cortez, 46, had been selling "significant quantities" of stamps online.

Investigators also learned that Cortez had increased the Kenner Post Office's reserve stamp stock by more than $600,000. Records revealed that Cortez, whose annual salary was a little over $70,000, had lost significant amounts of money at Harrah's Casino in New Orleans.

Detectives found that Cortez lost $220,000 in 2017 alone, and that, in total, he lost more than $667,000 since 2011, according to officials.

Records from Harrah's show that he withdrew thousands of dollars on a regular basis. Cortez also made several large deposits into his bank account, including $58,000 during a one-month period over the summer.

The criminal complaint also accuses Cortez of embezzling thousands of dollars from the Des Allemands Mennonite Church in Des Allemands, Louisiana, where he served as treasurer, according to Nola.com.

If convicted, Cortez faces a maximum sentence of 10 years in prison and a $250,000 fine.