COLUMBIA, S.C. (AP) — The brain of the former NFL player who killed five people in South Carolina before fatally shooting himself will be tested for a degenerative disease that has affected a number of pro athletes.

Chronic traumatic encephalopathy (CTE) has been shown to cause violent mood swings and other cognitive disorders. CTE can only be diagnosed in an autopsy.

York County Coroner Sabrina Gast told McClatchy Newspapers on Friday that she had gotten approval from Phillip Adams' family for the procedure to be included as part of his autopsy.

The Medical University of South Carolina will be working with Boston University, which has a CTE Center.

According to its website, the center conducts research on the long-term effects of repetitive brain trauma in athletes and military personnel.

On Wednesday, Robert and Barbara Lesslie, two of their grandchildren, 9-year-old Adah Lesslie and 5-year-old Noah Lesslie, and 38-year-old air conditioning technician from Gaston James Lewis was shot and killed by Adams at the Lesslie's residence, The Associated Press reported.

Lewis's colleague, Robert Shook, 38, was also shot. His cousin, Heather Smith Thompson, said he's "fighting hard for his life" at a hospital in Charlotte.

Evidence left at the scene, police said, led them to Adams as a suspect.

Law enforcement officials found Adams at his parents' home, where they evacuated his parents and tried to convince him to come out.

He was found in a bedroom dead of a single gunshot wound, York County Sheriff Kevin Tolson told The AP.

Results from the tests for CTE won't be available for months.

The disorder is typically found in those who've been subjected to repeated head trauma.

A study in 2017 found signs of the disease in 110 of 111 NFL players whose brains were inspected.

Adams' father said in an interview with a Charlotte television station that he blamed football for his son's problems, The AP reported.

In an interview with USA Today, Adams' sister said that her brother's "mental health degraded fast and terribly bad" in recent years.

The AP reported that family members noticed "extremely concerning" signs of mental illness, including an escalating temper and personal hygiene neglect.