An immigration consultant characterized by authorities as the mastermind of a marriage fraud scheme pleaded guilty Thursday in federal court in Sacramento.

Sergey Potepalov, 57, of Citrus Heights admitted to his role in a scheme that involved sham marriages, according to a federal Department of Justice news release. He is to be sentenced Aug. 15 by U.S. District Judge Morrison C. England Jr.

Potepalov, a naturalized U.S. citizen of Russian descent, was the leader of a scheme with 13 other defendants who were charged in July 2011 with conspiring to commit marriage fraud, to defraud the United States, to make false statements and to induce foreign nationals to enter and remain in the United States, according to court records.

Authorities said the scheme involved foreign nationals from Eastern Europe and Russia who paid up to five-figure fees to enter into sham marriages with locally recruited U.S. citizens in an effort to legalize their immigration status.

For foreign nationals, marriage to an American citizen is one means of obtaining lawful permanent residence in the United States.

To initiate that process, those who are outside the country must apply for a K-1, or fiancé, visa that enables them to travel to the United States to marry the citizen spouse.

Alternatively, foreign nationals who are already in the United States and entered the country legally may wed here and apply for lawful permanent residence based upon the marriage. Upon entering the United States, they might also apply for political asylum.

According to affidavits filed in this case, in 2002, Potepalov arranged with Keith O'Neil to enter into a sham marriage with a Russian national who had been denied naturalization.

Between 2003 and 2005, O'Neil accompanied Potepalov on three trips to Moscow and filed petitions for K-1 visas for four other foreign nationals.

The women were from Russia, Uzbekistan and Armenia, according to the news release, and all of the petitions were ultimately denied. In 2007, O'Neil entered into a second sham marriage with a Romanian national.

The other defendants charged in the indictment include six foreign nationals who allegedly attempted to obtain K-1 visas and green cards through the scheme and six local U.S. citizens who allegedly agreed to "marry" the foreign nationals in return for promised payments of up to $5,000.

In June 2009, U.S. Immigration and Customs Enforcement Homeland Security Investigations agents executed federal search warrants at Potepalov's home and business, seizing numerous boxes of documents relating to immigration applications as well as computer files.

Documents filed in the case revealed that participants in the scheme went to significant lengths to make the sham marriages appear legitimate, such as posing for wedding pictures together, establishing apartments in both spouses' names and rehearsing false answers for interviews with immigration officials.

The investigation into Potepalov's activities began in 2006 after Homeland Security Investigations agents received information from the U.S. Department of State's Diplomatic Security Service indicating that Potepalov was filing fraudulent visa petitions on behalf of Russian and Ukrainian nationals.

As the investigation progressed, HSI agents worked closely with the U.S Citizenship and Immigration Service's Fraud Detection and National Security Unit in Sacramento to identify foreign nationals who may have sought to benefit from the scheme, authorities said.

Call The Bee's Cathy Locke, (916) 321-5287.

© Copyright The Sacramento Bee. All rights reserved.

• Read more articles by Cathy Locke

Order Reprint