Nigerian man sentenced to 48 months’ imprisonment for investment fraud scheme

Date: Sept. 21, 2026

Contact: newsroom@ci.irs.gov

Brad Schimel, First Assistant United States Attorney for the Eastern District of Wisconsin, announced that on Sept. 18, 2026, Joseph James Nantomah (aka “The Black Mentor”), was sentenced to 48 months’ incarceration for committing an investment fraud scheme that resulted in a loss of more than $2,700,000 to investors across the country and abroad. 

According to court records, Joseph Nantomah entered the United States on a visitor’s visa from Nigeria in 2016. Within a few years, he had cultivated a false online persona alleging that he had built a multi-million-dollar real estate enterprise. Nantomah gave himself the moniker, “The Black Mentor,” and hosted conferences and classes in which he purported to share his knowledge of building success in the United States with people he duped into paying for his classes. Nantomah then used these classes to convince his “students” to “invest” in Nantomah’s real estate business. 

Nantomah’s online presence, his “Wealth Flow” conferences, and his claims of growing a successful real estate business were all part of his scheme to defraud. Between May 2020 and December 2024, Nantomah stole $2,762,798.37 from at least 39 victims. Nantomah targeted mostly Nigerian immigrants and people who were members of his church. Drawing on their shared cultural heritage and their belief in the American Dream, Nantomah convinced them to send him millions of dollars that he claimed he would invest in real estate. He promised significant returns on investment. In reality, Nantomah had no legitimate business or knowledge in real estate. He spent the majority of his victims’ funds on a lavish lifestyle that included private jets, luxury cars, expensive jewelry, and a yacht. Nantomah also spent significant sums of his victims’ money cultivating his false online persona, including purchasing an honorary doctorate degree for himself and his wife and paying celebrities to attend his conferences. 

At his sentencing hearing, United States District Judge Lynn Adelman focused on the extensive harm Nantomah caused his many victims and the fact that the people Nantomah chose to victimize were themselves working class immigrants. Judge Adelman noted that Nantomah’s scheme warranted a significant period of incarceration because it “went on for a long time, caused substantial loss, and dramatically impacted the lives of numerous victims.” Many victims spoke at the sentencing hearing and recounted the tremendous harm that Nantomah caused to them and their families. 

In addition to the 48-month period of incarceration, Nantomah was ordered to pay restitution to his victims in the amount of $2,762,798.37. He will serve three years of supervised release after his prison sentence. 

“As Judge Adelman noted, the victims were not wealthy people. They were working class immigrants who were devastated by this betrayal by someone they trusted,” said First Assistant U.S. Attorney Schimel. “I am so proud to work alongside the amazing investigation and prosecution team that worked tirelessly to put this con man in prison where he belongs.”

“Fraud like this runs on trust. Nantomah sold his victims the promise of opportunity, then used their hard-earned money to fund his own expenses and keep his scheme afloat,” said Robert J. Kuszynski, Acting Special Agent in Charge, IRS Criminal Investigation, Chicago Field Office. “For some victims, that meant losing retirement, education, and other savings they spent years building. IRS Criminal Investigation follows the money because numbers don’t care about the sales pitch, and in this case, the money told the real story.”

“Joseph Nantomah defrauded more than 30 victims in Wisconsin and across the United States. Nantomah misrepresented himself as a real estate investor who solicited others to invest with him by promising profits on purchasing, fixing, and flipping real estate. Instead of purchasing real estate with investor money, he utilized more than $2 million for his personal use,” said FBI Milwaukee Special Agent in Charge Alan Karr. “The FBI will continue to work side-by-side with our partners to protect the American people and their hard-earned money from schemes like these.”

The case was investigated by the Internal Revenue Service Criminal Investigation and the Federal Bureau of Investigation. The Securities and Exchange Commission and the Wisconsin Department of Financial Investigations also investigated Nantomah. The case was prosecuted by Assistant United States Attorney Julie F. Stewart.

IRS-CI is the law enforcement arm of the IRS, responsible for conducting financial crime investigations, including tax fraud, narcotics trafficking, money laundering, public corruption, healthcare fraud, identity theft and more. It is the only federal law enforcement agency with investigative jurisdiction over violations of the Internal Revenue Code. IRS-CI has 16 field offices located across the U.S. and maintains an international presence through attaché posts abroad.