- The article discusses the phenomenon of people often knowing or having some connection to the perpetrators of violent crimes before they commit their crimes. It highlights several cases where the perpetrators were known to their victims or the community, but their violent tendencies were not recognized or addressed prior to the incidents.

- The article suggests that this pattern of familiarity with the perpetrator is common in many high-profile cases of murder, mass shootings, and other violent crimes. It explores the potential reasons why people may not recognize the warning signs or take action to prevent these tragedies, such as a reluctance to believe someone close to them could be capable of such acts, a lack of mental health resources, or a failure to report concerning behaviors.

- The article emphasizes the importance of being more vigilant and proactive in identifying and addressing potential warning signs of violence, even among those we know well. It suggests that improved education, access to mental health support, and a willingness to report concerning behaviors could help prevent some of these tragic incidents from occurring.