Red Bank police found 65-year-old Winston Gant on his knees, bleeding from a gunshot wound to his left leg, after he was robbed on July 28.
Three days later, Gant died after hemorrhaging from his wound while hospitalized at Erlanger, according to a Hamilton County medical examiner report released Friday.
Before his death, he told police he was robbed by two black males.
Gant was the father-in-law of state Rep. Gerald McCormick, R-Chattanooga.
Crystal Williams, who was with Gant at the time of the shooting outside his residence and business -- Gant's Towing, 2401 Briggs Ave. -- identified 38-year-old Adrian "Pee Wee" Ladon Gustus as the shooter.
As of Friday afternoon, Gustus remained at large on the Top 12 wanted list for Hamilton County and most wanted list for the Tennessee Bureau of Investigation.
Segmund Jermaine Boyd, 39, turned himself in to Red Bank police on Thursday and told authorities Gustus was the gunman. He remains in jail without bond and is set to go before Red Bank Municipal Court Judge Johnny Houston at 3 p.m. Monday.
Williams and Boyd are married and have a child, but have been estranged for about a year, said Red Bank Police Chief Tim Christol. Investigators "have found nothing that connects her to this," he said.
Boyd and Gustus face charges of felony murder, aggravated robbery and especially aggravated robbery.
"Our family is very grateful for the tireless efforts of the Red Bank Police Department and all other cooperating agencies," McCormick said in a prepared statement. "I wish I could say that I am glad someone has been arrested but I am not. Instead I am saddened that a situation has occurred that has caused someone to be arrested. I pray for the people who did this. I don't think they understand the sorrow they caused."
According to police reports, Gant and Williams were outside when they were approached by two men who demanded money and ordered them to the ground. When Gant said he had no money, a brief struggle ensued and Gant was shot, the report said. Gant's cellphone and wallet and Williams' purse were taken, the report said.
Gustus has a prior robbery arrest, according to Hamilton County court records. He is out on bond with eight charges pending before the Hamilton County grand jury, including two counts of second-degree attempted murder after a November stabbing at Berle's Bar, 2407 Glass St., according to records.
Boyd has a prior theft conviction dating back to 2005, according to court records.
Anyone with information about Gustus' whereabouts may contact Red Bank police at 875-0167 or 877-2481.