Police said they believed he chose the one-room structure because it was nearby and had no security.
Several other neighbors said they had never seen Roberts angry. "I can't believe it," said Mary Fischer, who lives next door. Roberts was the driver who picked up milk from her son's dairy. "I have never heard him say an angry word."
An Amish family recalled how he accidentally ran over a wheelbarrow with his milk-hauling rig. He knocked on the door and calmly reported the incident.
Another driver, the family said, might have been angry that the implement was left where the delivery truck would hit it in the dark.
Roberts' father-in-law, Kenneth "Kenny" L. Welk, is a well-known retired milk hauler, friends said.
Like others in the area, Ranck, the bed-and-breakfast owner, expressed fear that Marie Roberts and their three children will suffer because of the killings.
He said Marie Roberts comes from "a real nice family."
Ranck and others said the community, where the Amish ride in horse-drawn buggies and avoid using modern technology, has its share of crime, but violence is rare.
Charles Roberts' parents live in a two-story home in nearby Bart, Pa. A blond woman who answered the door declined interviews yesterday. A dozen cars were parked nearby.
Douglas Birch wrote this article and reported from Baltimore. Josh Mitchell reported from Nickel Mines. Bradley Olson contributed to this article from East Earl, Pa. The Associated Press contributed to this article.