In a video message, Tisch said Tamura left a suicide note and claimed to be suffering from chronic traumatic encephalopathy (CTE), possibly from playing high school football. Tamura also blamed the NFL and asked that his brain be studied for signs of the degenerative disease.

The gunman, who said in a note he believed he had CTE, targeted skyscraper that houses the NFL's headquarters.

Shane Tamura, 27, is the suspect alleged to have shot and killed four victims while wounding an NFL employee. Tamura then fatally wounded himself. Further investigation into the shooting revealed that Tamura was targeting the NFL's offices, but "appeared to have gone to the wrong floor" in the 44-story skyscraper.