Christopher Vaughn Murder Trial: Jury Selection Begins This Week For 2007 Slayings (VIDEO)

Since his wife and children were found fatally shot in 2007, Christopher Vaughn has maintained his innocence, explaining that he narrowly survived a murder-suicide attempt masterminded by his wife.

But in the five years since the Oswego man was arrested and charged in the slayings, police have unveiled new evidence that promises to complicate the murder trial scheduled to begin next week.

Vaughn, 37, told police that his family was driving to a water park in Springfield when he pulled over on a frontage road, and exited the car to fix the luggage rack, ABC Chicago reports. Vaughn claims that his wife Kimberly fired shots at him, then at his children before shooting herself. The defense team says that Kimberly Vaughn was taking anti-seizure medication at the time that increases the risk of suicidal behavior.

But police say evidence indicates that Vaughn fired the shots that killed his wife and three children--Abigayle, 12, Cassandra, 11, and Blake, 8--and the shots that caused his injuries, according to Oswego Patch.

Vaughn was arrested on four murder charges during his family's funeral, and after five years of pre-trial hearings, a judge reopened the case file last June, the Chicago Sun-Times reports. Jury selection began Monday for Vaughn's trial--which will be held in the courtroom next to the murder trial of suspected wife-killer Drew Peterson.

Will County State’s Attorney’s office spokesman Chuck Pelkie told CBS Chicago that although the prosecution can no longer seek the death penalty in this case, his office "is ready and eager to move forward with" the trial. “It’s been a long time,” he told the station.