So, it appears from the article (although I haven't seen the original study) to be the following:
In the study, eight male high school shooters, including the two students responsible for the attack at Columbine, were analyzed based on personal and social factors noted in newspapers and the FBI document titled "The School Shooter: A Threat Assessment Perspective."...The researchers examined 10 different characteristics of cynical shyness and found that the school shooters fit this profile.
(1) They found a bunch of characteristics common amongst high-school "shooters"
(2) Then, they compared high-school "shooters" to these characteristics
(3) Finally, they found that high-school "shooters" fit the characteristics...
...common amongst high-school "shooters"
Wow, that's fascinating. (Maybe I misunderstood? I suspect the researchers somehow developed the criteria of "cynical shyness" some other way. Would be nice if the article said what that was.)