SHEFFIELD — A couple and their three young children were found dead Wednesday morning inside a house that was damaged in a fire.

The sister of one of the victims confirmed the deaths of Luke Karpinski and his wife, Justine Wilbur, both 41. The couple's 7-year-old twins, Alex and Zoe, and Marek, 3, also died, according to Kristen Wilbur, Justine's sister.

Flanked by fire and law enforcement officials, Berkshire District Attorney Andrea Harrington led a news conference Wednesday afternoon at Sheffield Town Hall.The fire was reported around 7:50 a.m. on Home Road, she said, and the house was engulfed in flames when crews arrived.

Firefighters knocked down the fire and entered the home about 9:15 a.m., and the fire was extinguished about an hour later. Crews found one body and continued searching the structure, Harrington said. Four more bodies were later found inside the home.

Harrington did not take questions at the news conference and called the investigation "complicated." Several local and state agencies are investigating, including the State Fire Marshal.

On Wednesday morning, several miles of Home Road were closed to nonlocal traffic, and members of the media were prohibited from entering.

State Police Detective Lt. Ed Culver said the road would remain closed, possibly until Thursday morning.

As of Wednesday evening, information about the fire remained scarce.

Kristen Wilbur said details of the tragedy were hard to come by.

"We weren't given much information," she said. "We were asking; we were told it was being investigated. We don't know if it was a fire, if there was an explosion and then a fire. We just don't know."

Karpinski's cousin, Tess Karpinski, said the family was declining to comment at this time.

Karpinski and Wilbur were Dalton natives. Karpinski worked from home as a federal chemical patent examiner. Wilbur specialized in patent law for Hoffman Warnick Intellectual Property Law, a firm in Albany, N.Y.

They began dating as seniors at Wahconah Regional High School and went on to careers in the patent industry, said Kristen Wilbur, who was on her way back to the Berkshires on Wednesday from her home in New Hampshire.

She said they spent about six years working in Virginia before moving back to Massachusetts and buying land in Sheffield in 2017. They lived in a trailer on the property until their house was completed.

December was their first Christmas in the new house.

"They called it a carriage house," Wilbur said. "The plan was eventually to build a larger house."

Wilbur said she was on her way to Lanesborough, where her mother lives.

"I'm still in shock," she said.

She had spoken to her sister Saturday, when they exchanged texts about a wagon she had seen and thought about buying for the children, her only nieces and nephews.

Wilbur said the loss cuts deep.

"They were smart, intelligent, good people — and good parents. And the kids were so cute," she said. "It's very sad. My father passed away five years ago, so that just leaves me and my mother."

Eagle staff writer Kristin Palpini contributed to this report.