Christopher Vaughn. Photo input: 8/15/12. Will County Sheriff's Office.

The Vaughn family, (upper left to right): Christopher, Kimberly, Abigayle, and (bottom from left) Cassandra and Blake are shown in an undated photo in front of Rosemont Theater in the Chicago area, where the Phoenix University graduation was held.

Blake Vaughn, 8; Christopher Vaughn, 32; Cassandra Vaughn, 11; Kimberly Vaughn 34; and Abigayle Vaughn, 12; smile in their Oswego home. Kimberly Vaughn and the three children were found shot to death in the family SUV in 2007. | Submitted photo

Christopher Vaughn, of Oswego, is on trial in Will County for the murder of his wife, Kimberly, and their children in 2007. | Will County Sheriff's Office via AP

Christopher Vaughn

George Lenard, attorney for Christopher Vaughn, departs during lunch break during the the Christopher Vaughn murder trial at the Will County Courthouse Tuesday, August 28, 2012, in Joliet. | Matthew Grotto~Sun-Times Media

Prosecutors (from left to right) Jim Long, Michael Fitzgerald and Chris Regis depart during lunch break during the the Christopher Vaughn murder trial at the Will County Courthouse Tuesday, August 28, 2012, in Joliet. | Matthew Grotto~Sun-Times Media

Illinois State Police Sgt. Gary Lawson returns from lunch break during the Christopher Vaughn murder trial at the Will County Courthouse Tuesday, August 28, 2012, in Joliet. | Matthew Grotto~Sun-Times Media

Prosecutors (from left to right) Chris Regis and Michael Fitzgerald depart for the day for the the Christopher Vaughn murder trial at the Will County Courthouse Tuesday, August 28, 2012, in Joliet. | Matthew Grotto~Sun-Times Media

Defense lawyers (from left to right) George Lenard, Steven Whitmore and Jaya Varghese depart for the day for the the Christopher Vaughn murder trial at the Will County Courthouse Tuesday, August 28, 2012, in Joliet. | Matthew Grotto~Sun-Times Media

Prosecutors (from left to right) Jim Long and Debbie Mills depart for the day for the the Christopher Vaughn murder trial at the Will County Courthouse Tuesday, August 28, 2012, in Joliet. | Matthew Grotto~Sun-Times Media

Prosecutors Debbie Mills (below) and Jim Long (top) return from lunch break during the Christopher Vaughn murder trial at the Will County Courthouse Wednesday, August 29, 2012, in Joliet. | Matthew Grotto~Sun-Times Media

Prosecutor Michael Fitzgerald returns from lunch break during the Christopher Vaughn murder trial at the Will County Courthouse Wednesday, August 29, 2012, in Joliet. | Matthew Grotto~Sun-Times Media

Defense attorneys Steven Whitmore (left) and Jaya Varghese (right) return from lunch break during the Christopher Vaughn murder trial at the Will County Courthouse Wednesday, August 29, 2012, in Joliet. | Matthew Grotto~Sun-Times Media

Defense attorney George Lenard returns from lunch break during the Christopher Vaughn murder trial at the Will County Courthouse Wednesday, August 29, 2012, in Joliet. | Matthew Grotto~Sun-Times Media