Police in Texas have searched the home of 68-year-old Thomas Matusiewicz.
The search warrant names his wife Lenore and his son David as suspects in a murder conspiracy.
The document describes surveillance video that shows father and son hugging in the courthouse lobby.
David Matusiewicz then went through the security checkpoint while his father, Thomas, stayed behind, apparently waiting for his victims.
Thomas Matusiewicz shot and killed his former daughter-in-law, Christine Belford, and her friend Beth Mulford, before exchanging gunfire with the police and then shooting himself in the head.
Two handwritten death certificates for Belford and her lawyer were found on his body.
Relatives have told Action News that Thomas Matusiewicz had recently been diagnosed with a brain tumor.
He may have decided to settle a score before taking his own life, and the search warrant says his wife and son are "suspected of intentionally and knowingly participating in a murder."
David Matusiewicz is now being held in federal prison for violating the terms of his probation. He served four years in jail and his mother Lenore also served time for kidnapping his three daughters who were in Belford's custody.
David and Thomas Matusiewicz drove here from their home in Texas for a court hearing on child support issues.
David's ex-wife, Christine Belford, brought her best friend with her for moral support because she feared Matusiewicz and his family.
In the meantime fearful courthouse employees returned to work today.
Chief Justice Myron Steele tells Action News the courts will be reevaluating security here and at all courthouses in Delaware.
One thing they're considering is moving the checkpoints to the outside doors.