From a New York Times article on the Kalamazoo, Mich., shooting suspect (bold mine):
Mr. Dalton, who was in custody on Sunday and was expected to face formal charges as early as Monday, had no criminal record. Neighbors described him as quiet and polite, though he caught their attention when he occasionally shot a gun out the back door of the house he shared with his wife and two children. He had worked for Progressive Insurance until mid-2011.
. . .
Sally Pardo, a retired nurse who lived across the street from him and his family, said she and her husband had always thought of Mr. Dalton as a “nice guy” who worked on cars in his spare time. But he used guns in a troubling manner and sometimes sounded a little paranoid, she said.
“He periodically shot his gun out the back door,” Ms. Pardo said. “He would shoot randomly into the air.”
James Block, 53, who said he had lived next door to Mr. Dalton for about 15 years, said he was “well-mannered” and pleasant.
What do you have to do to get your neighbors to say you weren’t a nice guy?
I found some other neighbor interviews.
Ed Gein: Neighbors agree that Ed could not have been “pleasanter” or more inconspicuous, although the suit of human skin he was gradually assembling on a dressmaker’s dummy “gave him a certain definite flair.”
Charles Manson: Neighbors described Charlie as a “nice guy” who “kept to himself,” although the family of dedicated cult followers who sometimes assembled in his backyard to chant and write things in blood “could shake your Tuesday up a little.”
John Wayne Gacy: Neighbors reported that John was a “nice guy,” known to the neighborhood for his paintings of clowns and gentle demeanor, though they admitted he had “eccentricities” including “lights that would come on at odd hours,” that “periodic frenzied sawing sound, like someone slicing bone” and “the mild smell of rotting human flesh that constantly emanated from beneath his floorboards.”
Unknown: Neighbors described William as a “nice, pleasant guy” who sometimes said “odd things.” “He would say, you know, just, wacky stuff, sometimes,” commented his next-door neighbor, “like, ‘I am the Zodiac killer’ or ‘I was responsible for those serial murders in Northern California in the ’60s and ’70s. I am Zodiac,’ or ‘Ma’am, what part of “I am literally the Zodiac Killer” don’t you understand?’ I never knew what to make of it. He liked casserole.”
Jeffrey Dahmer: Neighbors described Jeffrey as a “nice guy” who “took great care of his lawn” although they noted that “you generally would have to pass on whatever meat item it was he’d brought to the potluck” on account of “he was definitely a cannibal who would murder human beings and then store their parts in Tupperware.”
John Wilkes Booth: Neighbors said that John was a “nice guy” who “seemed like a real gentleman” except for one memorable incident when he “literally assassinated President Abraham Lincoln in front of me” but “the condo board had no issues with him.”
Jack the Ripper: Neighbors said that Jack was “terrific” and “had the most beautiful dahlias” and was “a dream to live next door to” except for the rare occasions when he would bring home a Victorian prostitute and viciously stab her to death.
I guess you have to give people the benefit of the doubt.
(Unrelatedly, neighbors said that Martin “seemed like a suspicious character” and “there was something off about him” and “he liked to block bridge traffic, was he involved in something, Carol? I knew it!” before being informed that Dr. King had in fact won a Nobel Peace Prize, not committed any crime.)