A fourth Nigerian will be sentenced Wednesday for his part in a scam that intercepted $11 million in tax refunds using identifications stolen mostly from Oregonians.

U.S. attorneys are seeking a 65-month sentence for Lateef Aina Animawun, 37, who will be sentenced in U.S. District Court in Eugene. They are also asking that he pay $1.98 million in restitution stemming from actual losses.

The case began in May 2013 when a Medford couple reported someone had fraudulently filed tax returns using their Social Security numbers and other personal information. Eventually, the case would involve nine federal agencies across the country and net the arrests of six Nigerian nationals.

Investigators say the Nigerians attempted to steal more than $91 million by filing at least 10,000 false tax returns, according to court documents and a release issued Tuesday by the Department of Justice.

Last week, Michael Oluwasegun Kazeem, 24, was sentenced to seven years in prison for his role conspiring to commit mail fraud, aggravated identity theft and mail fraud. He was ordered to repay $4.3 million in restitution and will be deported at the end of his sentence.

In August, Michael Kazeem testified against his brother, Emmanuel Oluwatosin Kazeem, 34, who was convicted by a jury for his central role in the scheme.

Investigators say a Vietnamese hacker provided Emmanuel Kazeem 91,000 taxpayer IDs stolen from Lincoln City-based CICS Employment Services, according to the release and previous reports. CICS performs pre-employment background checks, among other services, and directly lost $420,000 because of the fraud.

After the Medford couple reported the fraudulently filed tax returns, investigators learned the couple's federal refund had been deposited from a prepaid debit card into a bank account in a suburb of Chicago, while their state refund had been routed to a bank account in Texas.

The IRS ultimately issued search warrants at residences in Illinois, Maryland and Georgia, which yielded about 150 prepaid debit cards, tens of thousands of dollars in money orders, more than 50 electronic devices, about $14,000 in cash, and prepaid debit cards containing $12,000 in fraudulent tax refunds.

The discoveries prompted a joint investigation from the IRS, U.S. Department of Health and Human Services, Office of Inspector General, the FBI and others.

Starting in 2013, Michael Kazeem, while living in Lagos, Nigeria, used personal identification provided by his brother to obtain e-file PINs in taxpayers' names from the IRS website, the release says. He would then "wash" the stolen identities by connecting the IDs to banks and credit bureaus, allowing the return to skirt IRS authentication procedures. Michael Kazeem entered the United States in August 2014 on a student visa and studied chemical engineering in Georgia.

Starting in 2014, Emmanuel Kazeem and co-conspirators used the IRS' "Get Transcript" webpage to access more sensitive taxpayer information, from which 1,600 fraudulent returns were filed. Because of the ring's security breaches, the IRS discontinued the "Get Transcript" program in 2015, according to the release.

A search of email accounts tied to Lateef Animawun yielded 22,000 identities, according to a brief filed in court Thursday. Animawun "washed" his stolen identities to file returns using TurboTax, according to the court document.  Investigators found 40 "full and complete taxpayer transcripts" from his laptop in Georgia.

In May, co-conspirators Oluwatobi Reuben Dehinbo was sentenced to nine years in federal prison and ordered to pay $2.7 million in restitution, and Oluwaseunara Temitope Osanyinbi was sentenced to six years in prison and ordered to pay $876,161 in restitution.

In August, Emmanuel Kazeem, most recently of Bowie, Maryland, was found guilty of 19 counts of mail and wire fraud, aggravated wire fraud and conspiring to commit mail and wire fraud. He remains lodged in the Jackson County Jail pending sentencing in March 2018.

Lateef Animawun remains lodged in the Lane County Jail awaiting his Wednesday sentencing.

Oluwamuyiwa Olawoye, 30, will be sentenced April 19, 2018, in Medford. He remains lodged in the Jackson County Jail.

— Reach Mail Tribune reporter Nick Morgan at 541-776-4471 or by email at nmorgan@mailtribune.com.