The rampage, which started on a rural highway, did not fit the general pattern of previous mass shootings in the nation's endless series of such tragedies.
At least two heavily armed attackers opened fire on a holiday banquet at a social services center for the disabled Wednesday (Dec. 2), killing 14 people and seriously wounding more than a dozen others in a precision assault that looked "as if they were on a mission," authorities said.
"That's my boy right there," Flanagan wrote. "He got NEARLY double the amount that Eric Harris and [Dylann] Klebold got . . . just sayin."
Researchers think violence is no different. Although it's a somewhat recent area of focus - the Institute of Medicine held a workshop on the subject in 2012 - the evidence for contagion of criminal or dangerous behavior has lurked in academic research for decades.
Studies have shown that the aircraft hijackings of the 1970s were contagious. Product tampering - also contagious. So is highway speeding, rioting and even military coups. Contagion is especially pronounced in suicides.
In many of these events, the primary vector - what transmitted the behavior - was some form of mass media. Coverage of hijackings bred more hijackings. Coverage of suicides, particularly of famous people, had the same effect. In the month after Marilyn Monroe overdosed on barbiturates, suicides increased 12 percent nationally.
Mary Ellen O'Toole, a former senior FBI profiler who has worked on mass shootings, said, "It's only infective if they are entertaining a similar ideation."