Three relatives of the San Beardino terrorists who killed 14 in December were arrested Thursday on federal conspiracy, marriage fraud and false statement charges, the FBI aounced.

The arrests don’t appear to stem from any actions related to the terror attack, but rather a marriage-for-citizenship scam allegedly enacted between Enrique Marquez, Jr. and Mariya Cheykh.

Marquez is already in jail and awaiting trial for conspiring with one of the San Beardino attackers, Syed Rizwan Farook, in terror plots that never materialized. Marquez is also accused of supplying weapons to Farook and his wife for the San Beardino attack.

Marquez’s wife, Mariya Cheykh, 26, is charged with fraud and misuse of visa, permits and other documents. She’s also accused of perjury and two counts of making false statements to federal agents.

Tatiana Farook, 31, Cheykh’s sister, and her husband Syed Raheel Farook, 31, who is also Syed Rizwan Farook’s brother, were also arrested. Cheykh and Tatiana Farook are Russian immigrants.

The FBI said in a statement that Tatiana and Syed Raheel Farook “participated in the [marriage] conspiracy by, among other things, witnessing Marquez ad Cheykh’s wedding, taking staged family pictures of Maruqez and Cheykh” and other actions.