A New York man embarks on a murder spree, murdering his wife..

A New York man embarks on a murder spree, murdering his wife, parents, and himself across the state; he leaves a letter in his car.

A guy from Clarence, New York, left a letter in his car detailing that he intended a murder spree on Thursday morning, seconds before slaughtering three family members and killing himself.

Erik Bergum murdered his wife Mary Beth and mother Nancy Bergum, all 64, before joining his father Mark Bergum, also 64, at a shooting range.

"The kid actually began shooting at the range and then went ahead and murdered his father," Erie County District Attorney John Flynn said.

According to authorities, Erik then turned the pistol on himself. A message in his car proved that the rampage was planned recently. However, no motive was revealed.

"We don't know how long ahead of time it was planned," stated the district attorney. "Based on the memo we discovered, it was at the very least scheduled for Thursday morning."

"But we don't know if he thought about it for two weeks or a month. We're attempting to figure out what's going on."

Erik and Mary Beth's four children were at school when the family slaughter occurred.

"Every time I got a call, it was heartbreaking," Sheriff John Garcia said. "When the mother was discovered dead, when the wife was discovered dead. Thank goodness the children were in school."