The brother of slain boxer Isiah Jones has been arrested and charged with murder ... after prosecutors say he shot and killed the fighter following a dispute earlier this week.

According to officials, Timothy Lyman is accused of getting into an argument with Jones at around 6:20 PM on Monday in Detroit ... before shooting him in the face and fleeing the area.

Authorities say Jones was found unresponsive at the scene and was later pronounced dead.

Lyman was arrested on Wednesday -- and, according to prosecutors, he's now been charged with one count of second-degree murder, and one count of felony firearm.

He's due in court for a hearing in the case later Thursday.

According to Roshawn Jones, Isiah's longtime boxing trainer, Isiah was a "very great father" who "provided for his kids."

"He was a hard worker," Roshawn added in an interview with The Ring after the boxer's death. "Everyone is not perfect in life but he was a good human being. He’d make you smile and laugh and was a great role model in the gym."

Isiah -- a National Golden Gloves winner -- turned pro in 2016, and piled up a 9-7 record.

Roshawn has set up a GoFundMe for the fighter, explaining the money will go toward his funeral and his kids.