(MCT) — An Illinois State Police investigator has testified that Christopher Vaughn, charged with killing his wife and three children, may not be responsible for their deaths, a former member of Vaughn's defense team said.

Sgt. Robert Deel, who is no longer a crime scene investigator after prosecutors faulted his work on another murder case, testified that the evidence convinced him that Vaughn's wife might have shot her husband and children before killing herself, the former defense team member said. Vaughn suffered minor gunshot wounds in his wrist and leg.