Jim Haddadin/Nashua Telegraph A car crash near the intersection of routes 13 and 130 in Brookline, N.H., on Tuesday morning claimed the life of Katie Hamilton, 30.

Volunteer firefighter Stephen Whitcomb rushed to the scene of a Christmas Eve car wreck, not knowing whether the victim could be saved.

But at the nightmarish accident in New Hampshire, he made a heartbreaking discovery: The female victim was dead. She was his 30-year-old daughter.

Now, as officials investigate what caused the three-car accident that claimed the life of Katie Hamilton — and whether criminal charges are warranted — the small town of Brookline is mourning the loss of a woman beloved by the community of first responders.

"She would help us with our fundraisers and would do anything for anybody," Brookline Fire Chief Charles Corey told NBC News on Thursday. "She would always help us. If we had a big call, she would later come down and bring food for us."

Whitcomb is a 20-year volunteer and veteran of the fire department, Corey said. He ran a plumbing business with his daughter, a mother of three.

The family couldn't be reached for comment Thursday, but Hamilton's husband described to The Boston Globe how he spent Christmas morning with his three girls — ages 2, 4 and 9 — without their mother.

The 2-year-old wanted to know where Mommy was, Liam Hamilton said. His 4-year-old, who already knew what happened, responded, "Mommy died."

"I tried to make it normal," Liam Hamilton said of a day that should have been filled with joy and smiles.

His wife was on her way to work Tuesday morning after dropping off the girls at their grandmother's house. Just before 9:05 a.m., Hamilton was driving southbound on Route 13, preparing to turn left onto Route 130, when another car struck her 2006 Ford Explorer from behind, Brookline police said.

The force from the other vehicle, a 2009 Toyota Tundra pickup, caused Hamilton to veer into the northbound lane, where a 2004 Ford F250 pickup struck her broadside, police said.

Hamilton was pronounced dead at the scene; the drivers of the Explorer and the F250 were not injured.

Police identified the Tundra's driver as 31-year-old Greg Cullen. Brookline Police Chief William Quigley told NBC News that neither alcohol nor speed appeared to be factors in the crash, although "driver inattentiveness" could be a likely cause.

Cullen couldn't be reached for comment Thursday.

The Hillsborough County Attorney's Office said the case remains under investigation and will determine whether criminal charges would be filed. It declined to say whether Hamilton was wearing a seat belt.

The accident left Hamilton's Explorer mangled, with both the front and back of the car horribly crushed.

Liam Hamilton said he met his wife in 2005 in a plumbing class. He realized how close she was to her father and described their dad-and-daughter bond as "tight," according to the Globe.

On her Facebook page, Hamilton often shared photos of her family in celebration, including the holidays last year, when they had "the best Christmas ever."

"My girls and I are rocking the drums, air guitar, singing and jumping around. Love being a mom:)," Hamilton wrote in a post.

In another, she couldn't hide her happiness: "I don't know what to say my life is perfect:)"

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