SPRING, Texas – An arrest warrant has revealed new details surrounding the arrest of a man charged with murder in Montgomery County.
The Montgomery County Sheriff’s Office said 18-year-old Isaiah Mayham has been charged with murder in connection to the death of 19-year-old John Dennis Holmes III.
Holmes was found dead in the middle of a Spring area street in the 300 block of Raypine Drive on July 16. He had sustained multiple gunshot wounds.
The warrant alleges that Holmes communicated with someone on Instagram about meeting up to trade firearms. An associate of Holmes indicated that he was looking to acquire a pistol format assault rifle, or ARP, in exchange for a less valuable pistol and 20 grams of marijuana. Police believe the Instagram user Holmes was communicating with was Mayham.
Around the time of the shooting, Holmes had planned to meet up with the user to make the deal in the parking lot of an apartment complex.
When Holmes arrived, the user—believed to be Mayham—asked him if he was alone and to confirm what vehicle he was in. Once he knew Holmes was alone, investigators believe Mayham planned to ambush his car and rob him. It’s unclear whether or not the murder was a part of the plan at this time.
Surveillance footage obtained from a neighboring apartment shows a male wearing a black hoodie with a bright pattern and blue jeans running away from the shooting. The man in the video appears to be holding two guns, one in each hand. One of the weapons had a distinct red magazine.
A search warrant from Meta Platforms—the company that owns Instagram—uncovered information that linked Mayham to the surveillance footage and the Instagram account Holmes was communicating with.
The warrant found a photograph of a firearm with a red magazine, like the suspect was seen holding in the neighbor’s surveillance footage. A video was also found showing a male wearing a black hoodie a similar pattern to the one seen in the footage. Another video, recorded after the shooting, shows a male displaying a pistol with similar characteristics to the one that Holmes possessed prior to the attack.
If that wasn’t compelling enough, investigators uncovered an audio message from the account, during which the speaker describes shooting Holmes and stealing his gun and marijuana. The speaker also says he burned the clothes he was wearing and used alcohol to wipe down the guns involved in the attack.
Authorities identified the speaker in the audio message, as well as the other content collected from the account, to be Isaiah Mayham.
Mayham has been further tied to the crime by GPS data. He was on pre-trial release under the supervision of Harris County Juvenile Probation, facing a separate murder charge from 2023. He was supposed to wear an ankle monitor as a condition for his release, and the GPS data from that monitor pings him at the scene during the crime and fleeing the area immediately after.
Initially, deputies arrested a different 20-year-old man in connection to Holmes’ murder, but video surveillance helped prove that man’s alibi.
John Holmes mother told KPRC 2 reporter Corley Peel on the phone she is grateful an arrest has been made and she is hoping for justice for her son.
According to Mayham’s warrant, the woman who has custody of him lives at the apartments where Holmes was killed. KPRC2 knocked on her door, but no one answered.
Family of 2023 murder victim speaks
On Thursday, KPRC 2 Reporter Corley Peel spoke with the family of 21-year-old Moses Gama. Mayham is accused of killing the young father in May 2023. Gama’s cousin, Marc Carillo, said he planned to meet someone at an apartment complex off North Post Oak Lane to buy a PlayStation.
“He felt safe going to go buy this console because it was in a nicer area. But unfortunately, tragedy struck,” said Carrillo.
Investigators say Mayham shot Gama and robbed him. The loving father’s 2-year-old son and pregnant wife were in the car as he was gunned down.
Mayham was arrested months later and charged as a juvenile. Records show Harris County Juvenile Probation had him under supervision as he waits for trial.
Carillo said he is not surprised Gama is accused of another violent crime.
Carillo said Gama’s wife gave birth to a baby boy month’s after his death. He said its been heartbreaking having to watch Gama’s son’s grow up without a father.
“Every single time you look at the babies, they look just like Moses. Moses was a great dad. He was he was a very bright, very outgoing and very caring person. Just thinking about all the memories that we shared with him, it hurts. And, you know, we’re still we’re still in pain,” said Carrillo.