BOSTON (AP) — Eleven people were indicted Thursday for allegedly arranging sham marriages and submitting fraudulent green card applications to circumvent immigration laws, Massachusetts U.S. Attorney Rachael Rollins announced.

Rollins said the defendants, who live in California, were indicted on conspiracy to commit marriage fraud and immigration document fraud in connection with operating a large-scale marriage fraud “agency” in Los Angeles. Eight of them were arrested in California and scheduled to appear Thursday in federal court there, then appear in Boston at a later date, Rollins added.

Rollins said the charges stem from hundreds of sham marriages that were arranged between foreign national “clients” and U.S. citizens from 2016 until last month. One of the clients lived in Massachusetts.

The agency allegedly prepared and submitted false petitions, applications and other documents to substantiate the sham marriages and secure adjustment of clients’ immigration statuses for a fee of $20,000 to $30,000, Rollins added.

Six of the defendants are Philippine nationals living in Los Angeles. One is from Brazil and the others are residents of Lancaster and Palmdale, California.

Rollins said marriage fraud is a serious crime that threatens the integrity of the nation’s lawful immigration system. She said the defendants did further harm by allegedly submitting false applications claiming the clients had been abused by their alleged American spouses, so they could apply for lawful permanent resident status without their spouses being involved.