ABC News December 23, 2019

Man sought for questioning in fatal stabbing of NFL quarterback's brother

WATCH: NFL player's brother fatally stabbed outside Nashville bar

A 23-year-old man is one of four people being sought for questioning by police in the fatal stabbings at a Nashville bar of two men, including the brother of San Francisco 49ers' backup quarterback C.J. Beathard, authorities said.

Nashville police say they are eager to talk to Michael D. Mosley about the violent confrontation early Saturday at The Dogwood bar that claimed the lives of Beathard's 22-year-old brother, Clayton Beathard, and Paul Trapeni III, 21, a student at Rhodes College in Memphis.

Investigators are asking for the public's help in locating Mosley, who is "strongly believed to have definitive information about the murders," police officials said in a statement.

Nashville Police
Police in Nashville, Tenn., released this image with a statement saying that they are looking for Michael D. Mosley, 23, for questioning in relation to a stabbing that killed two people on Dec. 21, 2019.

Mosely is one of four people who were at the bar during the fatal fight that police are seeking to question. He is the only one police have identified.

"Mosley has been identified as being present both inside and outside of The Dogwood bar, including when the fight occurred," according to the police statement.

Clayton Beathard and Trapeni were stabbed around 3 a.m. on Saturday during a fight that occurred outside the bar when they saw a woman being subjected to unwanted advances from a man and attempted to intervene, police said.

Both victims were rushed to Vanderbilt University Medical Center, where they died. A third man was also stabbed in the confrontation, but survived, police said.

Daniel Shirey/Getty Images, FILE
C.J. Beathard of the San Francisco 49ers warms up prior to a game at Levi's Stadium on Nov. 1, 2018, in Santa Clara, Calif.

No arrests have been made in the slayings.

"Clay was an amazing, big and soft-hearted human being with an undeniable love for the Lord," Clayton Bethard's parents, country music songwriter Casey Beathard and Susan Beathard, said in a statement to The Tennessean.

Clayton Beathard was a junior at New York's Long Island University, where he was the starting quarterback this past season on the school's football team.

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"He had his family’s, friends' and teammates' backs even to a fault," the parents said. "I wish he would have been more inclined to take the high road but he hated 'wrong.'"

Nashville Police
Police in Nashville, Tenn., released this image made from video of a man who was present during a fatal stabbing at a bar on Saturday night, Dec. 21, 2019.

C.J. Beathard, who is a backup quarterback for the 49ers, immediately took leave from the team to join his family in Nashville.

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Following the 49ers thrilling last-minute victory over the Los Angeles Rams on Saturday, head coach Kyle Shanahan told his players that C.J. Beathard had given him a message to relay to them.

"He could barely talk, but he said to me, last thing he said as he walked out the door is, 'You guys go out and win this game,'" Shanahan said. "This game doesn't mean anything compared to his brother, but you guys know C.J."

Tony Avelar/AP
A sign for San Francisco 49ers quarterback C.J. Beathard is shown on a parked car at Levi's Stadium before an NFL football game between the 49ers and the Los Angeles Rams in Santa Clara, Calif., Dec. 21, 2019.
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The 49ers' organization released a statement saying they were "shocked and deeply saddened" by Clayton Beathard's death.

"We extend our heartfelt sympathies to C.J. and the entire Beathard family as they cope with the unthinkable loss of a loved one," the team said.