The brother of San Francisco 49ers quarterback C.J. Beathard was killed in Nashville Saturday morning. (Lachlan Cunningham/Getty Images)

Clayton Beathard, the younger brother of San Francisco 49ers backup quarterback C.J. Beathard, was fatally stabbed early Saturday morning outside of a Nashville bar.

Clayton Beathard, 22, and Paul Trapeni III, 21, were stabbed in the side and died at Vanderbilt University Medical Center. The two were friends and high school football teammates at Battle Ground Academy near Nashville.

Beathard was a junior quarterback at Long Island University who had appeared in seven games last fall before missing the rest of the season due to injury.

Nashville Police said in a statement they believe things began with an argument over a woman.

“The fatal stabbings appear to have resulted from an argument over a woman that began inside Dogwood Bar and then turned physical when the parties went outside. Multiple persons were involved in the outdoor fight during which the two men were both fatally stabbed in their sides. A third stabbing victim, a 21-year-old man, was treated and released,” the statement read.

The attacker is still at large.

C.J. Beathard was a third-round pick in 2017 and has started 10 games for the 49ers in his career.

Their grandfather is Bobby Beathard, a Pro Football Hall of Fame executive.

Statement from the San Francisco 49ers pic.twitter.com/w1mjxV1AeB — San Francisco 49ers (@49ers) December 21, 2019

Nashville Police are requesting the public’s help in identifying the man in surveillance photos who is being sought for questioning. If you have information, contact Crime Stoppers at 615-742-7463.

More from Yahoo Sports: