Toddler and Father Killed in Montana After Man Drives Into Family and Started Shooting: Police

Police said the attacker had a "prior relationship" with the father's sister, who was also injured at the scene

A father and his young daughter are dead following a tragic shooting in Montana Sunday.

On July 17, shortly before 9 p.m., a man reportedly, purposely drove into a family from central New York near Glacier National Park, Syracuse.com reported. Then, he got out of his car and opened fire.

According to a statement from the Glacier County Sheriff's Office posted to Facebook, when law enforcement arrived on the scene at East Glacier Park, they found "two deceased males, two critically injured females, and one critically injured 18-month old."

An investigation determined that the suspect, Derick Amos Madden, exited his vehicle with a shotgun after crashing into a tree, the statement said. He began shooting at the people "he had just hit or attempted to hit," before fatally shooting David Siau, 39. He continued shooting at the family, wounding Christy Siau, 40 and McKenzie Siau, 18 months. The toddler would not survive her injuries.

David Siau, Christy Siau and McKenzie Siau. Facebook

Madden then attacked Christina Siau, 30, with a knife, the statement said. According to Syracuse.com, Christina is McKenzie's aunt and David's sister. Despite her injuries, Christina fought back and fatally wounded the attacker, who died at the scene.

The investigation found that Madden had been in a "prior relationship" with Christina and was "suffering from mental health issues."

"The attack was isolated to this incident with a clear nexus between the victims and Madden," the statement said. "This investigation continues and detectives are working tirelessly to find all the details and circumstances surrounding this horrific incident."

According to the sheriff's office, two other minors were present at the scene, but were able to flee without injury. Christy, Christina and McKenzie were transported to Indian Health Service in Browning, where the 18-month-old was pronounced dead.

Christy and Christina were moved to "a higher level of care with critical injuries," the release added.

The village of East Glacier Park has a year-round population of 300 and is on the Blackfeet Indian Reservation, Syracuse.com reported.

David, Christy and McKenzie are from Syracuse, while Christina lives in East Glacier Park, the sheriff's office said.