An American citizen charged with supporting the Islamic State received thousands of dollars from fake eBay transactions via a global financial network run by a now-dead official of the terrorist group, according to an FBI affidavit unsealed Thursday.

The alleged ISIS operative, Mohamed Elshinawy, who is in his 30s, received $8,700 from people associated with the terrorist group, including five payments through PayPal, The Wall Street Journal reported.

Elshinawy was arrested in 2016 for his alleged ISIS ties. His PayPal payments came from a company owned by Siful Sujan, according to the FBI affidavit.

Sujan, ISIS director of computer operations, was killed in a drone strike in Syria on Dec. 10, 2015, a person familiar with the case told the Journal.

He founded a British technology company that had offices in Bangladesh, according to the FBI affidavit, and was setting up offices in Turkey.

According to the 2016 indictment, filed under seal in January in U.S. District Court in Baltimore, Elshinawy allegedly sold computer printers on eBay as a cover to receive the ISIS payments through PayPal.

Authorities have said Elshinawy told investigators he was to use the funds for "operational purposes" — a possible terrorist attack in the U.S., for instance — though he said he "never planned to carry out any attack," the Journal reported.

Instead, Elshinawy told investigators he took money from "thieves," according to the affidavit.

He has pleaded not guilty to supporting ISIS and is awaiting trial while in federal custody.

His lawyer declined to comment, the Journal reported.

The case illustrates how the Islamic State is tapping the online financial world to finance its global terrorist activities, according to the report.

Some methods being used include fundraising on social media, student-loan withdrawals and online lending fraud, according to the Financial Action Task Force, an intergovernmental body that makes recommendations on combating terrorism activities.

One former Treasury Department official likened trying to police such forms of financing terrorism to "looking for a needle in a massive haystack."

A spokesman for eBay Inc. told the Journal the company "has zero tolerance for criminal activities taking place on our marketplace" and it was working with law enforcement on the case.

In addition, a PayPal Holdings Inc. representative said it "invests significant time and resources in working to prevent terrorist activity on our platform.

"We proactively report suspicious activities and respond quickly to lawful requests to support law enforcement agencies in their investigations."