“We have no Swedish precedents,” he said. “Unless we go back as far as the Nordlund massacre on the steamer Prins Carl. So they’ve had to base their research on American surveys that have been made during the last few decades.”
He blew at his pipe to see if it was clear and then started to fill it as he went on. “Unlike us, the American psychologists have no lack of material to work on. The compendium here mentions the Boston strangler; Speck, who murdered eight nurses in Chicago; Whitman, who killed sixteen persons from a tower and wounded many more; Unruh, who rushed out onto a street in New Jersey and shot thirteen people dead in twelve minutes, and one or two more whom you’ve probably read about before”
He riffled through the compendium.
“Mass murders seem to be an American specialty,” Gunvald Larsson said.
“Yes,” Melander agreed. “And the compendium gives some plausible theories as to why it is so.”
“The glorification of violence,” said Kollberg. “The career-centered society. The sale of firearms by mail order. The ruthless war in Vietnam.”
Melander sucked at his pipe to get it burning and nodded.
“Among other things,” he said.
“I read somewhere that out of every thousand Americans, one or two are potential mass murderers,” Kollberg said. “Through don’t ask me how they arrived at that conclusion.”
“Market research,” Gunvald Larsson said. “It’s another American specialty. They go around from house to house asking people if they could imagine themselves committing a mass murder. Two in a thousand say, ‘Oh yes, that would be nice.'”
— From The Laughing Policeman (1970), by Maj Sjöwall and Per Wahlöö
Plus ça change, plus la même chose.