(CNN) A woman close to the Parkland, Florida, school shooter called an FBI tip line in early January to describe a young man with an arsenal of knives and guns who was "going to explode" and said she feared him "getting into a school and just shooting the place up." The FBI admitted last week that it had failed to act on the tip. Nineteen-year-old Nikolas Cruz killed 17 people when he stormed his former school, Marjory Stoneman Douglas High School, with an AR-15 style gun last week. In the days since the massacre, people who knew Cruz have described a troubled young man who was often at odds with law enforcement and made violent posts online. The FBI and local police have revealed that they had received several warnings about his behavior.

Source: CNN February 23, 2018 22:37 UTC