Suspected internet fraudster, Hushpuppi and his associate, Olalekan Jacob Ponle, also known as Mr Woodberry were arrested in Dubai, where they lived, in June.
They were later taken to the US where they appeared in a Chicago court on 3 July.
The BBC quoted a spokesman for the US Department of Justice as saying that Hushpuppi was expelled from Dubai and was not extradited.
“In my opinion, the FBI and the government here acted illegally when they kidnapped him from Dubai without any legal process to do so.
“There was no extradition, there were no legal steps taken, there were no court documents filed, it was simply a call to the FBI. He is not a citizen of the United States, the US had absolutely no authority to take him.”
