Shane Tamura, the suspect in the July shooting at a New York City office building that houses the NFL's headquarters, was posthumously diagnosed with chronic traumatic encephalopathy (CTE), the New York City Officer of the Chief Medical Examiner confirmed in a statement obtained by ESPN on Friday (September 26).

Tamura, 27, who shot and killed four people before killing himself at 345 Park Ave., was previously reported to have asked that his brain be studied for CTE, a disease widely suspected to be caused by repeated blows to the head, which has been linked to the league and the sport of football as a whole, prior to the incident. The references to the NFL in the three-page note found on Tamura were described as being vague by sources with knowledge of the situation, ABC News reported.

"We continue to grieve the senseless loss of lives, and our hearts remain with the victims' families and our dedicated employees," the NFL said in a statement obtained by ESPN. "There is no justification for the horrific acts that took place. As the medical examiner notes, 'the science around this condition continues to evolve, and the physical and mental manifestations of CTE remain under study.'"

CTE cannot be diagnosed with certainty among living people as it can only be confirmed through an autopsy in which specialists study specific changes in the brain, however, doctors can suspect it based on symptoms and past head trauma. Symptoms of CTE include memory loss, mood changes, confusion and trouble thinking clearly among patients.