the 17-year-old is in critical condition at a local hospital. i believe clair davis was is an innocent young lady. she is an innocent victim and i believe that she probably was simply in the wrong place at the wrong time. reporter: the sheriff says pierson purchased the shotgun and ammunition legally. it is our strong belief that he came to this school with that weapon and with multiple rounds and his intention was to utilize those multiple rounds to cause harm to a large number of individuals. reporter: while investigators are still trying to figure out what triggered pierson robinson says one thing is clear. he is someone who victimized an innocent young lady by an act of evil and in my opinion deserves no notoriety and certainly no celebrity. investigators say they have spoken to the shooter s parents and that they have searched both their homes, they didn t say what they found if anything but police say they believe the gunman did, in fact, act alone.
and a 17-year-old girl shot in the head. martha shade takes us through how it happened. reporter: friday s or deal took a minute and 20 seconds. karl pierson walked into the school, fired several shots including one at a female student before killing himself, he said. the sheriff says the 18-year-old entered the school carrying a shotgun, multiple rounds of am mission, a machete and three molotov cocktails in his backpack and made his way to the library and ignited one of the bombs and turned the gun on himself as the school s resource officer approached. the response from the school resource officer, the response from the unarmed security officer was absolutely critical to the fact that we did not have additional injury and/or death in this particular matter. reporter: the female student clair davis was sitting with a friend when pierson stormed in and shot her.