SHEFFIELD — District Attorney Andrea Harrington said Tuesday that her office has ruled out other suspects in what early on was deemed a murder-suicide after a family of five was found slain in their burning home.
"We have a good sense that we know what happened in this case," she told The Eagle. "But because of the nature of this case, because it is so hard to understand for a lot of different reasons ... we're [still] investigating because we know how important it is to speak for the victims ... and for the community to have a sense that they know what happened."
Harrington also said her office is still awaiting autopsy reports from the state Office of the Chief Medical Examiner, as well as results of testing of remaining evidence at the crime laboratory.
Another delay in releasing final results to the press and public are investigation reports that have not been approved. So far, 60 out of 68 reports are approved, she added.
Details released to the public about the evidence that led to the murder-suicide theory have been scarce since the early morning March 13 slayings. Investigators believe that Luke Karpinski, 41, killed his wife and three children before setting fire to the house and taking his own life.
The deaths of Karpinski, his wife, Justine Wilbur, 41, and their 7-year-old twins, Alex and Zoe, and Marek, 3, shocked and rattled a community that is still grappling with a possible motive.
The couple, both Berkshire County natives, worked in the patent industry, and had just finished building their dream house on Home Road.
A funeral for the entire family was held in Dalton on April 27.
Harrington said from the start that the investigation would be complex, and released some information early on — that an accelerant had been used to spread the fire, that Wilbur's body was found downstairs, and Karpinski and the children's bodies were found upstairs.
Sources familiar with the investigation told The Eagle and The Boston Globe that authorities thought Wilbur might have suffered knife wounds.
And obituaries for the family say that Wilbur and the children died on March 12, and Karpinski, on March 13.
Harrington said another reason why the investigation is still open is that detectives are pursuing other leads, or "pieces of information that they want to follow up on."
"It's a very thorough investigation," she added.
When asked if Karpinski may have tried to make it appear as if someone else had killed the family, Harrington said she would not speculate. But she did say it was likely that Karpinski thought the fire would consume the house.
"It appears that the intention was for the house to burn to the ground and that didn't happen," Harrington said. "And because that didn't happen, we have a lot more evidence than we would have otherwise."
Heather Bellow can be reached at firstname.lastname@example.org or on Twitter @BE_hbellow and 413-329-6871.