Anthony "T.J." Cunningham also played wide receiver and defensive back at the University of Colorado.
CNN  — 

Anthony “T.J.” Cunningham, a former Seattle Seahawks player and assistant principal at a Colorado high school, has died after being shot during a parking dispute, the Arapahoe County Sheriff’s Office said.

Cunningham, 46, an NFL safety during the 1996 season, was shot by a neighbor early Sunday and taken to a hospital, where he died the next day, the sheriff’s office said via Twitter.

The neighbor, Marcus Johnson, 31, was originally held on attempted murder charges, but the charges were amended to first-degree murder after Cunningham’s death, authorities said.

It’s not clear whether Johnson, who is being held without bond, has an attorney.

Cunningham texted Johnson hours before the shooting, sheriff’s spokeswoman Deborah Sherman told CNN.

“It was a dispute that morning, they were texting back and forth, and then they said let’s settle this at the school,” she said.

The shooting occurred in the parking lot of Eaglecrest High School in Aurora, where deputies found Cunningham with gunshot wounds, according to a probable cause document. After the shooting, a sheriff’s officer said, Johnson called deputies to say that he had shot his neighbor. The handgun was in his car.

Witnesses told investigators the two men had had an “ongoing parking dispute,” according to the officer. Cunningham’s brother told investigators he accompanied the former player to the parking lot, where the two neighbors were to “box it out,” referring to their dispute. Their homes are about a mile from the school.

Cunningham and Johnson walked toward each other, yelling obscenities, the court document said. Johnson, who said Cunningham had a bottle, shot him three time in the head and chest, according to the document. Cunningham’s brother told investigators the former NFL player was unarmed.

Cunningham was pronounced dead Monday afternoon.

Aurora Public Schools said in a statement, “We are deeply saddened to learn that one of our assistant principals, Anthony (TJ) Cunningham passed away.”

Counselors were available at Hinkley High School, where Cunningham worked, throughout the week, the statement said.

Cunningham played wide receiver and defensive back at the University of Colorado. He was the 209th overall pick in the 1996 NFL draft by Seattle, according to the Seahawks website.

The Colorado Buffaloes said on Twitter that Cunningham was “a tremendous part of the CU community and touched countless others beyond Boulder.

“We were deeply shocked and saddened to learn of the death of T.J. Cunningham. He was a good family man and had a strong passion for working with young people.”

CNN’s Melissa Alonso contributed to this report.