Potentially dangerous behavioral traits are often noticed and even reported, sadly to no avail. In other instances, people notice something is awry; but for some reason, dismiss this behavior and fail to notify anyone about their suspicions.To some extent, both of these scenarios played out in the case of 19-year-old Nicolas Cruz. The February 14, 2018 shooting at Marjory Stoneman Douglas High School in Parkland, Florida, resulted in 17 tragic deaths, untold emotional damage, a grieving community and nation, and thousands of young people empowered to change the status quo. Although part of the discussion may involve gun control laws, another important aspect is the need for people to get better at recognizing the signs of violent tendencies and following up on their instincts. Many classmates who knew Cruz since grammar school not only repeatedly reported his behavior at school, but sadly weren\u2019t surprised when they found out what he had done. In less than five years at middle school and Stoneman Douglas, Cruz racked up more than two dozen incidents prior to being expelled from the high school in January 2017. Escalating Warning Signs As early as age 9, Cruz got into a rock-throwing fight with another boy and later bit a neighbor\u2019s ear. As a teen, he seemed to enjoy harming small animals, expressed a passion for guns and knives, and began introducing himself as a \u201cschool shooter.\u201d In the years prior to the school massacre, the Broward County Sheriff\u2019s Office was alerted numerous times about Cruz\u2019 behavior, including responding to violent incidents targeted at his adoptive mother and brother. It has been reported police visited Cruz\u2019s home(s) a total of 39 times before the school shooting. According to a November 2016 Florida Department of Children and Families investigative report, crisis workers from a South Florida mental health facility were called to hold Cruz for a psychiatric evaluation after he sent out a Snapchat video in which he cut his arms and said he wanted to buy a gun. The report noted that \u201cMr. Cruz has fresh cuts on both his arms\u201d and in 2015, he had a "Nazi symbol drawn on his book bag" and "hate signs on a book bag stating, 'I hate n-----s.'" When his adoptive mother died, Cruz and his younger brother Zachary were taken in by their mother\u2019s friend Rocxanne Deschamps, who lives in Lantana. Deschamps called 911 three times about Nikolas in the brief period he lived with her, which was less than a month. The first time came after she found a receipt for a gun and bullets in his room, the second upon finding an empty gun box and the last time when he punched holes in the wall after getting in a fight with her son. She finally gave him an ultimatum to get rid of the guns or leave her home. On March 20, Deschamps appeared at a press conference accompanied by her lawyer, the first time she has spoken publicly since the shooting. \u201cI did everything I could to warn law enforcement about what could happen. I wanted to protect not only my own children, but also anyone else who might be at risk of being harmed,\u201d she said. \u201cI also wanted to protect Nikolas from himself.\u201d After this, Nikolas returned to Parkland, where he lived with James and Kimberly Snead at the bequest of their son, who knew him from the JROTC program at Stoneman Douglas. The couple was aware of his gun arsenal, but made him keep the firearms and ammunition in a locked safe. They knew he was depressed about his mother\u2019s death, but had no idea about his disturbing past. Although Cruz was not taking medication, the Sneads say he was open to mental health treatment and a meeting with a therapist was scheduled the same week as the shooting. \u201cWe had this monster living under our roof and we didn\u2019t know,\u201d Kimberly said. \u201cWe didn\u2019t see this side of him.\u201d At age 17, Cruz had already made alleged threats about attacking a school. The FBI received two tips about Cruz, specifically about the threat he posed to schools, yet the bureau never followed up on the leads. The Broward County Sheriff\u2019s Office received "third-hand information" from a neighbor's son who claimed Cruz had talked about shooting up a school on Instagram, where he posted pictures of himself with guns. On social media, he also bragged about target shooting in his backyard and killing animals. General Warning Signs Although school shooters are all unique, certain characteristics have emerged from recent mass school shootings: \tTend to be loners \tA lack of remorse after doing something wrong \tActing out violently or showing a proclivity to violence \tAnnouncing in advance plans to commit acts of violence \tExhibiting a strong fascination or obsession with firearms \tBoasting about easy, illegal or unsupervised access to firearms \tStudying previous mass shootings \tShowing aggression or reacting inappropriately to seemingly minor things \tHaving real or perceived feelings about being picked on or persecuted by others \tShowing little interest in educational pursuits \tA sudden drop in academic performance In a frightening turn of events, Zachary Cruz was arrested on March 20 after he trespassed on the campus of Stoneman Douglas. Authorities are worried he is exhibiting similar red flags as his older brother, and are being careful to not make the same mistakes again. The Broward Sheriff\u2019s Office filed a petition for a \u201ctemporary risk protection order\u201d under the state\u2019s new gun law, identifying Zachary Cruz as someone who \u201cposes a significant danger of causing personal injury to himself or others by having a firearm.\u201d A judge set a bond of $500,000 and involuntarily hospitalized Zachary for a mental health evaluation under the state\u2019s Baker Act. Far too often, questions remain unanswered when teenage killers take their own lives. Hopefully, this case will yield useful insights about both Nikolas and Zachary Cruz\u2019 mental state, which may in some way help prevent future school shootings.