Law enforcement officials seeking a motive for a shooting at Nashville’s Antioch High School on Wednesday morning are examining alarming social media posts and writings tied to a teenager police say shot and killed a 16-year-old girl.

The shooter was “significantly influenced by web-based material, especially that found on non-traditional sites that most would find harmful and objectionable,” police said.

One student is dead and another is wounded after a third student opened fire with a pistol Wednesday at Antioch High School in Nashville, Tennessee, police said. The 17-year-old shooter then shot himself and died,