Mr. McIntyre had already pleaded guilty to two counts of aggravated robbery and was found guilty of a third count tied to the incident, but his lawyers argued that he should not be convicted of murder because he was not the gunman in the killing. Six others were charged in the robbery that left Ethan Walker, 21, dead in July 2016. Prosecutors argued that Mr. McIntyre knew a shooting would occur when he and the others agreed to commit a robbery in hopes of finding drugs and money.

The rapper, who was 16 at the time, was certified as an adult to stand trial. He had been placed on house arrest with an ankle monitor when he escaped in the spring of 2017, setting off a manhunt for what the United States Marshals Service deemed a “violent fugitive.”

According to prosecutors, Mr. McIntyre committed a separate murder in San Antonio while on the run, and he has also been charged with beating and robbing a 65-year-old man in an Arlington park. Both trials are forthcoming.

Brian W. Butcher, a lawyer representing the families of Mr. Walker and two other alleged victims of Mr. McIntyre, said in a statement that civil lawsuits against the rapper were ongoing. “I am glad a Fort Worth jury delivered justice,” he said, but added that “justice will not be fully complete until every penny of profit from McIntyre’s music is awarded as compensation to his victims.”