ALEXANDRIA, Va. -- A ringleader of a scheme to arrange phony marriages between cash-seeking U.S. citizens and illegal aliens seeking green cards was sentenced Friday to nearly 3 1/2 years in prison.

The sentence is one of the longest handed down in the investigation of one of the Washington area's biggest immigration scams.

Samuel Acquah of Bowie, Md., pleaded guilty in October to conspiracy to commit immigration fraud. The longtime patent examiner at the U.S. Patent and Trademark Office admitted taking $200,000 from the fake marriages.

Mark Owusu, another man identified by prosecutors as a ringleader, received 21 months in prison Friday.

"Sham marriages, the number that you engaged in, the scheme that you engaged in, do serious injury to the proper administration of our immigration system," U.S. District Judge T.S. Ellis III said.

The scheme involved an estimated 1,000 phony marriages. Most of those involved were from Ghana.

Immigrants would pay as much as $6,000 to be introduced to a "spouse," usually on the day of the marriage. They would then be coached on how to lie to immigration inspectors to make the marriage seem real.

Acquah, a Ghanaian immigrant who has master's and law degrees, said he arranged more than 100 of the phony marriages only to help his fellow immigrants. Immigrants who marry U.S. citizens can get a visa to stay in this country immediately, instead of having to wait years, and can shorten the route to citizenship.

The judge, however, was not swayed.

"That's a mansion you built," Ellis said, holding up a picture of Acquah's $775,000 house. "You did this for greed. You didn't do it to help anyone. So get that notion out of your head."

Since the fraud ring was broken up in September, 20 of 22 people charged have pleaded guilty in Alexandria. Most have been sentenced to probation or to prison time already served. Most of the immigrants will be deported.