There are new details from the investigation into what authorities say was a quadruple murder-suicide in Sheffield, Massachusetts.
Berkshire District Attorney Andrea Harrington says evidence from the crime scene shows alleged assailant Luke Karpinski used accelerants including propane to set the Home Road residence on fire after killing his wife Justine Wilbur and their three children. Describing the evidence against Karpinski as "overwhelming," Harrington said Monday night that no firearms were found at the scene. Karpinski is said to have taken his own life after committing the four murders.