In a 2023 study, Boston University CTE Center found that 345 out of the 376 former NFL players investigated had CTE, a brain disorder related to head injuries.

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.