Millions of taxpayers dollars trafficked through food stamp fraud went to terrorists who funded their activities at home and abroad, according to an explosive report from the Government Accountability Institute (GAI).

The report from GAI, where Breitbart News Senior-Editor-at-Large Peter Schweizer serves as president, highlighted several instances where money obtained through Supplemental Nutrition Assistance Program (SNAP) benefits fraud went to fund acts of terrorism, including the 1993 World Trade Center bombings and the 2013 Boston Marathon Bombing.

Although this method of using food stamp fraud money for terrorism has been around since the 1980s, it gained notoriety when New York City detectives testified before a Senate subcommittee about the 1993 World Trade Center bombings.

Detectives told the committee that $125 million in food stamp fraud had “unwittingly” gone to terrorist activities.

One of the masterminds of the 1993 World Trade Center bombings, Mahmud Abouhalima, funded the attacks by operating a million-dollar food stamp fraud scheme out of a video store in Brooklyn.

But the U.S. government did not pinpoint how a lot of these terrorists used money from food stamp fraud to fund their attacks until shortly after the September 11 attacks in 2001.

The U.S. Treasury Department and the U.S. Department of Agriculture’s (USDA) Office of the Inspector General (OIG) identified that many terrorists would get away with funding their illicit activities by using businesses known as “hawalas” to launder money.

A “hawala”— which is an Arabic term defined in English as transfer (or trust)— is a method of transferring money through informal agents from international networks, and many Muslim immigrants settled in western countries use the “hawala” method to transfer funds to family members.

GAI, citing a U.S. Treasury report, found that more than $7 billion flows into Pakistan alone through hawalas every year.

Because of the informal, simple nature of the transaction, the “hawala” method has also been popular among criminals and terrorists to launder money from the U.S. to the Middle East, Africa, and Asia without a paper trail.

In one such instance in 2015, federal agents discovered couriers for these “hawala” networks traveling with cash-filled suitcases on flights leaving the United States for East Africa out of Sea-Tac Airport in Seattle, according to the report. The act of transporting the cash itself was not illegal, but it raised suspicion among federal authorities.

One federal investigator analyzing the financial records of the hawalas found that ten of the couriers working for those networks had been on federal welfare benefits.

Investigators say it is very difficult to track the money moved around through hawalas, even though the federal government has known about the use of hawalas and their alleged role in financing terrorism for years.

But as federal investigators became more familiar with the welfare fraud mechanisms used to fund terrorist activities after the September 11 attacks, investigators have cracked down on a number of instances where terrorists have used the benefit fraud for such purposes.

In 2006, a judge sentenced a Chicago grocery store owner to more than four years behind bars for defrauding $1.4 million from the nation’s food stamp program and using it to fund terrorist activities carried out by Palestinian Islamic Jihad.

In 2011, the FBI arrested Waad Ramadan Alwan and Mohanad Shareef Hammadi, both Iraqi refugees, on federal terrorism charges for sending “money and weapons to Iraqi insurgents from the U.S.” Alwan became a refugee in 2009, citing persecution in his native country, when he settled in Bowling Green, Kentucky. After briefly holding a job in the area, he moved into public housing and collected welfare payouts.

In 2013, federal investigators discovered that Islamic militants Dzhokhar and Tamerlan Tsarnaev, who carried out the Boston Marathon bombings, had been receiving more than $100,000 in federal welfare assistance over ten years. The Tsarnaev brothers, who had emigrated to the U.S. from Kyrgyzstan, had been receiving cash, section 8 housing, and food stamps.

Federal lawmakers have also become aware of these illicit means of transferring money, and have introduced bills to stop “hawalas” and similar money laundering activities. In May 2017, Sen. Chuck Grassley (R-IA) and Sen. Dianne Feinstein (D-CA) proposed legislation that would prohibit the practice of money laundering through hawalas.