The Berkshire District Attorney’s office is confirming that an accelerant was indeed used to start Wednesday’s fire in Sheffield. Berkshire District Attorney Andrea Harrington said in a media release last night that the investigation is complex and ongoing, but they have uncovered overwhelming evidence suggesting that Luke Karpinski killed his wife and children prior to committing suicide.

Killed Wednesday morning at 1343 Home Road were Luke Karpinski and his wife, Justine Wilbur, both 41, their seven-year-old twins, Alex and Zoe, and three-year-old son, Marek. It was speculated last week that Karpinski may have killed his wife, Justine Wilbur, before setting the fire intentionally. Autopsy results were not available yesterday from the Office of the Chief Medical Examiner.