A New Hampshire man who was found dead with his 4-month-old daughter shot himself, authorities said Tuesday after an autopsy.

Miles Deuse, 39, and his 4-month-old daughter, Makenzie, were found dead Sunday morning in a Hillsboro home. The gut-wrenching discovery was made inside a first-floor apartment on Bridge Street.

An autopsy determined that Miles Deuse died from a gunshot wound to the head and that the manner of death was suicide, the New Hampshire Attorney General's Office said in a statement. The cause and manner of Makenzie Deuse's death remain under investigation.

"It's very tough to wrap your head around," neighbor Kittery Durgin said Monday.

She's known Deuse since high school.

"He certainly was just a good, kind person, so I would imagine as a parent, he was that same way," Durgin said.

Investigators have not said who made the initial 911 call, but they made clear that the public was never in danger.

"All I can say is that it was a self-contained situation and it appears at this time that all parties have been identified," Cherniske said Monday.

With two lives cut short, and a community left shaken, family and friends are still desperate for answers.

"There would be nothing that would make me think that such a tragedy could happen, but who would know, who would ever see that coming," Durgin said.

NBC10 Boston reached out to the baby's mother, but hasn't heard back. The baby's grandmother said the family is asking for privacy at this difficult time.