An Upstate New York family's vacation to Montana has ended in shocking, brutal tragedy.

Bethany Siau via GoFundMe
Bethany Siau via GoFundMe

39-year-old David Siau, along with his wife and three children, was visiting his sister near Glacier National Park away from their home of Pompey, NY. While they were near the Park's entrance on Saturday night, a pickup truck veered off the road and attempted to run down the Siaus.

After he crashed into a tree, the driver exited the vehicle with a shotgun and proceeded to fatally shoot David and then fire another shot at David's 18-month-old daughter, still in her mother's arms, as the rest of the family was fleeing for cover.

He then attacked David's sister with a knife, and during their struggle she managed to fatally wound the attacker who died on the scene.

"Terrible and Unspeakable"

David was pronounced dead on the scene and his 18-month-old was taken to a nearby hospital where she was pronounced dead. David's wife and his sister were critically injured and airlifted to a hospital for intensive treatment. The Siau's other two young children are now in the custody of their grandparents.

Getty Images
Getty Images

According to the Glacier County Sheriff's Office, the gunman was Derick Madden, an Oklahoma resident who had previously been in a relationship with David's sister. There was “with a clear nexus between the victims and Madden” and he had previously been diagnosed with mental health issues.

There has been an outpouring of grief in Pompey, Syracuse, and New York's Baptist Church communities. The Siaus were very active members of the ABC and many have expressed their condolences and loss over Facebook.

John Siau, David's father, released a powerful video statement via the FBI on Wednesday night.

Grieve, be sad, but don’t harbor anger about what has happened. What we have seen is actually the result of somebody who has harbored anger in his own life and allowed it to fester and allowed it to grow and develop into something very terrible and unspeakable.

A family member has started a GoFundMe to raise money for the Siaus. At the time of writing, more than $110,000 has been raised.

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