David Matusiewicz (inset right) is the son of Thomas Matusiewicz, who opened fire inside a Delaware courthouse last month, killling David's ex-wife and her friend.
Federal authorities have laid out their reasons for wanting to revoke the probation of a former Delaware optometrist whose father shot and killed his ex-daughter-in-law and another woman before taking his own life.
Officials filed court documents Tuesday outlining several alleged probation violations by David Matusiewicz, who was sentenced to four years in prison in 2009 after kidnapping his three daughters and taking them to Central America. They include violating restrictions against being around guns or ammunition, and not truthfully disclosing his whereabouts and activities.
A probation hearing for Matusiewicz is set for Thursday.
Matusiewicz's ex-wife, Christine Belford, and a friend, Laura Mulford, were killed by Matusiewicz's father, Thomas, at the New Castle County Courthouse on Feb. 11. Thomas Matusiewicz then exchanged gunfire with police before taking his own life.
David and Christine had been fighting for years over custody of their children and his parents had both been involved in the family turmoil.
On the morning of the courthouse shooting, Thomas Matusiewicz was accompanying David to a child support hearing at the courthouse. Both parents traveled up from Texas to Delaware with their son.
In the days following the shooting, investigators found a cache of guns and ammunition inside the home where Lenore and Thomas lived in South Texas and at a nearby storage facility. They also found a letter left to their daughter, instructing her on what to do if they did not return home.
Investigators have named both David and his mother Lenore as suspects in the courthouse shooting case.