Three individuals associated with one of the San Bernardino aggressors have been captured over claimed marriage extortion.
The sibling and sister-in-law of shooter Syed Rizwan Farook were among those held after attacks in California.
The third individual captured is the wife of Enrique Marquez Jr, a companion of Farook who confronts charges himself in connection to the dangerous assault.
Fourteen individuals were executed when Farook and his wife, Tashfeen Malik, opened flame at an office party in December.
The killings were portrayed by powers as the deadliest fear assault on US soil since 9/11.
The three captured are being hung on charges of scheme, marriage misrepresentation and false proclamation charges, authorities said.
Mariya Chernykh, a Russian national, is blamed for wedding Enrique Marquez in a migration trick, the US Department of Justice said in an announcement.
Her sister is hitched to Farook’s sibling and each of the three face intrigue charges associated with the marriage.
The attacks on Thursday were led at homes in the urban communities of Corona and Ontario.
Farook and Malik were killed hours after the assaults, in a police shoot-out after an auto pursue.
Mr Marquez was captured not long ago. He denies plotting terrorism and supplying weapons.