Police said the suspect later turned himself in at the Galveston Police Department.
LEAGUE CITY, Texas — A Magnolia man has been charged with murder after a 37-year-old woman was found shot to death Monday afternoon inside a car at a League City apartment complex, police said.
Police identified the suspect as Isaiah Johnson, 38. Relatives identified the victim as Joanna Walton. Officers found Walton behind the wheel of a silver Toyota Corolla at the Harbor Walk Apartments on FM 518 after a shooting call around 2:25 p.m. Monday. Police said Johnson and Walton had a child together, and investigators continued to review witness statements, surveillance video and court records tied to earlier cases involving the pair.
Surveillance video described by police and witnesses showed Walton’s car entering the parking lot shortly after 2 p.m. A red SUV then came from a nearby carport and drove toward the area where Walton had parked. Witnesses said they heard several faint pops about two minutes later. Police said the SUV stayed nearby for about 30 seconds before leaving the complex. A witness told investigators he saw a man walk up to Walton’s car and fire 11 shots.
Officers and fire department personnel found Walton dead inside the Toyota with multiple gunshot wounds. Police said Johnson left the area in a Hyundai Santa Fe and turned himself in at the Galveston Police Department about two hours later. He was booked into the Galveston County Jail. Authorities have not said whether a weapon was recovered, and the full motive remained under investigation.
Court records reviewed after the shooting showed earlier allegations involving Johnson and Walton. In 2023, police said Johnson tried to shoot Walton, but the gun jammed. Investigators said he then pistol-whipped her. Records show Johnson later pleaded guilty, received 30 days in jail and was placed on 10 years’ probation. He also was ordered to complete a battering intervention program.
Police said Johnson was still on probation when he was accused last July of breaking into Walton’s apartment. An affidavit said Johnson sent Walton threatening text messages after the alleged break-in. Records show a warrant in that burglary case was issued in August 2025, but police said it was not served until Johnson surrendered after Monday’s shooting.
Johnson appeared in court Tuesday, where his bond was set at $360,000. The murder case remained active, and prosecutors were expected to review police reports, video evidence, witness accounts and records from the prior cases as the charge moved through Galveston County courts.
As of Thursday, Johnson remained accused in the fatal shooting, and police said the investigation was ongoing. The next major step is the filing and review of court records tied to the murder charge.
Author note: Last updated July 2, 2026.