Mother, brother of double murder suspect arrested for alleged plot to kill witnesses Joshua Federico was charged with murder in August.

The mother and brother of a double murder suspect are now under arrest themselves after allegedly conspiring to kill witnesses to their family member's slayings.

Joseph Federico and Wendy Federico, both of Chesterfield, Virginia, were arrested on Friday after police alleged they took part in the murder-for-hire plot.

The murder-for-hire plot was allegedly directed by the jailed Joshua Federico -- the brother of Joseph and son of Wendy -- who was arrested in August and charged with the murders of his estranged wife and her new boyfriend.

Joseph Federico, 41, has been charged with three counts of conspiracy to commit capital murder, solicitation to commit capital murder, attempted capital murder and two counts of felony obstruction of justice.

Wendy Federico, 63, was charged with three counts of conspiracy to commit capital murder and two counts of felony obstruction of justice.

In addition to the arrests of his mother and brother, Joshua Federico's friend Constantine Trikoulis was also allegedly involved in the plot to kill witnesses. He has been charged with three counts of conspiracy to commit capital murder, as well as two counts of felony obstruction of justice and accessory after the fact to first-degree murder.

Already saddled with two murder charges from August, Joshua Federico will now face three counts of conspiracy to commit capital murder -- for allegedly trying to organize the murder of three witnesses to his crime.

The FBI and Virginia State Police also assisted in the investigation.

Joshua Federico, 44, and his estranged wife, Sarah, were engaged in a bitter separation battle, according to divorce papers acquired by Richmond ABC affiliate WRIC. He accused her of adultery in the papers, while she said he was guilty of "extreme cruelty," stole money from her and even caused her to have a car accident.

Laura Miller, another friend of Joshua Federico, was also arrested on Friday for assisting him after the double murders in August.