KTVT reports that Kim Lene Williams was taken into custody just before 3:00 a.m., and charged with a single count of capital murder.
She is being held on a $10 million bond.
Her husband, Eric Williams, (L) was arrested on Saturday morning for allegedly making terroristic threats against city officials. He is being held behind bars on a $3 million bond.
Sources told KTVT that Williams is also expected to be charged with capital murder in relation to the deaths.
Eric Williams was fired last year after being convicted of stealing computer equipment from the county. Assistant District Attorney Mark Hasse and District Attorney Mike McLelland prosecuted the case against Williams.
A probable cause affidavit says Eric Williams sent an email, one day after the McLellands' bodies were discovered, implying there would be another attack if authorities didn't respond to various demands. The email was sent from Eric Williams' personal computer. Authorities arrested him on Saturday and charged him with making a terroristic threat.
He was being held on $3 million bond on that charge.
Williams lost his elected position as justice of the peace after he was convicted of stealing three computer monitors from an office. McLelland and Assistant District Attorney Mark Hasse - who was shot and killed in an apparent ambush outside a courthouse in January - prosecuted that case.
Hasse was killed in January outside the county courthouse. McLelland and his wife were found shot to death in their home last month.
Eric Williams had been questioned and tested for gunpowder in relation to the January murder of Hasse, and then again after the McLellands were killed in March.
On Saturday investigators served a search warrant on a Seagoville storage facility which was rented out to Eric Williams. Inside, they found about 20 guns and a white Ford Crown Victoria that matches the description of a vehicle spotted near the McLelland home on the night of the murders.