A Prison Cell Call Center: Georgia Inmate Pleads Guilty to Impersonating Deputy U.S. Marshals by Phone

The defendant and the setup

Per the DOJ release, Robert "Bo" Nnanwubas, 29, was incarcerated at Calhoun State Prison in Morgan, Georgia, when he and others conspired to impersonate federal agents and defraud health care workers across the country.

Per the plea agreement, the conspirators used contraband cell phones and Voice over Internet Protocol (VoIP) technology to call victims while impersonating law enforcement, namely, Deputy U.S. Marshals.

The script

The release describes a consistent pitch:

1. A "Marshal" told the victim that a subpoena had been issued for her to testify in court.
2. Because she had not appeared, a warrant had supposedly been issued for her arrest.
3. The warrant could be "quashed" if she sent money through Zelle or another digital payment system.

In one call to an area victim in Seattle, the caller claimed to be "Deputy Marshal Gary Hartnett" and asked her to call back what appeared to be a Seattle number. The callers said two subpoenas had been sent to her workplace, claimed a gag order was preventing her from consulting a lawyer or law enforcement, and demanded $2,000 or she would be arrested. They even told her that she would have to turn herself in at the federal courthouse at 700 Stewart Street in Seattle. The release notes, the schemers used as many correct details as possible. That victim did not pay.

The money

In March 2022, Nnanwubas' Zelle account received about $15,000 from eight victims. Three more victims sent another $5,300 through PayPal and Venmo. In the plea agreement, he agreed to pay $15,300 in restitution.

Prosecutors said they would request that eight months in federal prison be added to his state sentence at sentencing, which was set for March 12, 2024, before U.S. District Judge John C. Coughenour. The Federal Bureau of Investigation (FBI) investigated, with help from the U.S. Marshals Service.

"Legitimate government workers will not call and demand payment via Zelle, Venmo or some other digital means," Acting U.S. Attorney Tessa M. Gorman said.

Why this matters for voice providers

The scheme combined contraband phones, VoIP calling and callback numbers that looked local to the victim. Each of those pieces runs through a provider somewhere. Know Your Customer checks, traffic analytics and prompt responses to traceback requests are how carriers keep this kind of traffic off their networks.

The bottom line:

Government impersonation calls don't require a large call center. A handful of people, VoIP and a convincing script were enough to target professionals across the country.

Key takeaways

1. Targeted professions are a pattern. Here the callers focused on health care workers.
2. Local-looking callback numbers add credibility and deserve scrutiny from originating providers.
3. Digital payment demands are a hallmark. Zelle, PayPal and Venmo all appear in this case.
4. Small dollar cases still get prosecuted. Federal charges followed roughly $20,000 in payments.
5. "Gag order" claims that isolate victims from advice are a recurring script element.