HARTFORD — A 20-year-old woman and her adoptive father were shot and killed inside a pickup truck Thursday, and the suspect was found dead of a self-inflicted gunshot in a case connected to the slaying of an infant.

The suspect was identified as 45-year-old Steven Pladl, the father of the female victim, Katie Pladl. The father and daughter had been arrested on incest charges and a 7-month-old boy found slain Thursday in Knightdale, North Carolina, was their biological child, according to a lawyer for Steven Pladl.

"We're trying to make sense of all the factors that led up to this senseless taking of life," Knightdale Police Chief Lawrence Capps said.

Officers responding to reports of gunfire around 8:40 a.m. in New Milford, Connecticut, found two victims inside the truck with a window shot out, police Lt. Lawrence Ash said. Police were searching for the suspect's vehicle, a Honda minivan, when he was found dead inside the vehicle several miles away in Dover, New York.

Authorities said the motive for the shooting was still under investigation.

Around the same time the shooting was reported, police in Knightdale found the body of the infant, Bennett Pladl. Steven Pladl's mother had called police to conduct a welfare check on the home after a disturbing phone conversation with her son, Capps said. Police found the infant alone in the house.

Found slain in the pickup truck with Katie Pladl was her adoptive father, Anthony Fusco, 56, Capps said.

Rick Friedman, a Virginia attorney who had been representing Steven Pladl in the felony incest case, said he had breakfast with his client only a month ago and had no indication that such violence was possible.

"This really bothers me a lot because nobody ever could have predicted this. If anybody had a remote idea anybody was in harm's way there would have been no bond set," he said. "There was just absolutely no prior notice anything would happen to these people."

As part of the bond requirements, Friedman said, the father and daughter were not supposed to communicate at all with one another. He said Katie Pladl had been living in New York with her adoptive parents.

Jeff Weinzievl, a New Milford resident who lives near the intersection where Katie Pladl and her adoptive father were found, told the Connecticut Post he was feeding his horses when he heard six to eight shots from what sounded like a semi-automatic weapon.

"It scared the bejesus out of the horses," he said. "A lot of people hunt out here, but I knew this something was wrong with this. It was quite scary."

A nearby school was locked down as a precaution.