The Berkshire Eagle  reports accelerant was likely used to set a fire during the apparent murder-suicide that took the lives of three young children and their parents this week, according to a source familiar with the circumstances of the fire.

Investigators also are looking into whether Luke Karpinski stabbed his wife, Justine Wilbur, before setting their Home Road house on fire Wednesday, the source said.

Also, an unnamed official told The Boston Globe that detectives are trying to determine whether Wilbur, 41, had been stabbed first.

The first 911 calls came early Wednesday to report a structure fire with heavy smoke. In an initial search, firefighters found Wilbur's body downstairs. Karpinski's body was found in a second search upstairs along with those of 7-year-old twins Alex and Zoe, as well as Marek, 3.

Berkshire District Attorney Andrea Harrington has said the deaths are being investigated as a murder-suicide, with Karpinski, 41, the likely assailant.
In response to requests for comment, Luke Karpinski's cousin gave the following statement: