A Kenyan national was sentenced Tuesday to one year in federal prison for her role in a marriage fraud scheme that paid residents of several Maine cities and towns thousands of dollars to marry men and women from African nations who were facing deportation.

U.S. Attorney Thomas E. Delahanty II said the sentencing of Margaret Mwihaki Kimani, 30, of Worcester, Mass., brings to a close a “major marriage fraud conspiracy investigation” that took nine years to complete and resulted in the felony convictions of 28 people, including 13 Mainers.

Kimani was sentenced in U.S. District Court in Bangor to one year in prison and three years of supervised release for conspiring to defraud the United States by seeking to become a permanent resident, or green card holder, according to Delahanty.

Kimani, who came to the U.S. in 2001 on a visitor’s visa, paid a Lewiston man to marry her in 2003, according to documents filed in U.S. District Court. At the time her visa had expired. The couple then filed documents with U.S. immigration authorities to adjust her status, allowing her to stay in the country.

But after her marriage partner backed out of the scheme, Kimani filed a petition under the Violence Against Women Act, which allows aliens who are subject to abuse to apply for permanent residency without the knowledge or consent of their spouse.

Delahanty said Kimani lied about the domestic abuse to immigration officials. Relying on false claims, immigration authorities granted her lawful permanent resident status.

Her spouse was not prosecuted.

“America’s legal immigration system is not for sale and we will move aggressively against those who willfully compromise the integrity of that system simply to enrich themselves,” said Bruce Foucart, the special agent in charge of U.S. Immigration and Customs Enforcement’s Homeland Security Investigations unit. “Immigration benefit fraud is a serious crime. Not only does it potentially rob deserving immigrants of benefits they rightfully deserve, it also creates a security vulnerability that could be exploited by criminals and others who pose a danger to our community.”

Since the federal government’s investigation began in 2005, investigators identified more than 40 sham marriages in Maine. Not every case was prosecuted because in some instances the statute of limitations expired.

Foucart, in a telephone interview Tuesday night, said that all of the immigrants, including Kimani, were living in Massachusetts at the time their marriages were arranged by brokers in Maine.

They were all from the African nations of Kenya, Uganda, Zambia and Cameroon with visas that had expired or were close to expiring, according to authorities.

Two sisters, Angela Roy and Torri Patterson, who were living in the Lewiston-Auburn area, were paid to find men and women who were willing to enter into a fake marriage, Foucart said. He said the sisters, mostly by word of mouth, located potential marriage partners in Lewiston, Auburn, Portland and the Newport area.

Foucart said significant sums of money were exchanged. Maine residents who married a foreigner typically were paid between $1,000 and $1,500. In some cases, the Maine residents would be paid a bonus if they had to appear with their spouse before an immigration official.

The marriage arrangement involved filing marriage papers at local city and town halls and having wedding photographs taken. Thousands of dollars were involved in each transaction, including payoffs to the brokers.

“Everyone (involved) got their cut,” Foucart said.

Foucart said most of the Maine residents who got married as part of the scheme had criminal records or were in desperate situations.

Roy and Patterson were arrested and convicted in 2011. The sisters served sentences of 10 and six months, respectively.

Foucart said Roy and Patterson served as field agents for the operation’s ringleaders: Rashid Kakande and James Mbugua. Kakande was sentenced in April 2012 to 19 months in prison. Mbugua fled after being charged and released on bail and remains at large, according to Delahanty.

Gail Fisk Malone, an assistant U.S. attorney based in Bangor, prosecuted nearly all of the cases.

She said Roy and Patterson’s mother, June Roy White of Newport, was sentenced in 2011 to three months in jail for her role in the marriage-fraud scheme.

Malone said in a telephone interview Tuesday night that most of the participants from Maine were already in relationships but were not married, and had children or partners with whom they lived.

One marriage that began as part of the scheme stood out for Malone. She said the couple was not prosecuted because after meeting and getting married, they apparently fell in love and lived together as a couple.

Dennis Hoey can be contacted at 791-6365 or at:[email protected]