The man suspected in a trio of interstate incest-linked homicides Thursday had called his victims in Wingdale, New York, before driving 600 miles up from North Carolina to ambush and kill two of them, police say.

Steven Pladl, the 42-year-old suspected gunman, pulled up alongside his biological daughter and her adoptive father at the intersection of routes 7 and 55 in New Milford just before 9 a.m. Thursday. Then he opened fire with an AR-15-style rifle, gunning them down in the street before taking off, police say.

Investigators have since moved their pickup truck from the intersection to police headquarters.

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Police released 911 calls Friday from Pladl's mother, who frantically told them her son had left the baby dead in North Carolina and then driven up to New York to kill "his wife" and "her father." In New Milford, separate 911 callers reported seeing someone open fire on the truck.

"Someone just went by and shot someone in the truck," a caller says in a recording released by authorities. "The car pulled up, went around him and shot a whole clip full into his head."

New Milford found Katie Pladl and her 56-year-old adoptive dad, Anthony Fusco, shot dead in the pickup truck. About 16 miles away in Dover, New York, police there found Steven Pladl in another vehicle, dead of a self-inflicted gunshot from the same rifle.

Pladl and his daughter, 20-year-old Katie Pladl, had been estranged until a few years ago. Police say that when they met, they allegedly began a romantic relationship that produced a baby boy -- who police say they also found dead Thursday morning in Pladl's home in Knightdale, North Carolina. The Pladls both were charged with felony incest in February.

As part of her bond release on that charge, Katie Pladl returned to her adoptive family.