Kennedale police confirmed the arrest of Devin Holland in connection with Carl Wilson's death.
Cell phone records, social media feeds, forensic evidence and witness statements all point to him as the killer, police said.
Wilson was gunned down outside a Kennedale car wash on Jan. 12, likely because of an argument that started at school over a girl.
Police said Holland has ties to a Tarrant County gang, but it's still unclear if the gang played any part in the crime.
"The story he told up front was not the story we were able to verify through our evidence we were able to gather, so we zeroed in on him being the person responsible," said Kennedale Police Chief Tommy Williams.
Evidence leading to Holland's arrest includes witnesses who told police Wilson was supposed to fight another student after school at the nearby car wash.
Twenty to 30 people gathered to watch the fight, including members of the Trill Fam street gang, known for their violent acts, according to an arrest affidavit.
The affidavit says there was another teen with Wilson who said, "They were going to fight or he was going to get a thump...street slang for a gun."
A shooting witness told detectives that "Devin Holland stepped out of the group and shot Carl Wilson...when Wilson fell to the ground...observed Devin Holland stand over him and shoot him at least two more times."
Wilson was not a gang member, police said. The 18-year-old was a single father and star athlete who hoped to play football in college after graduation.
"It's just senseless," said Wilson's guardian, Lisa Tennison. "No reason for them to have taken Carl away from me, from everyone…his family, his sister, his grandmother, his biological mother, his son mostly."
Martin High football coach Bob Wager says Wilson's death has brought the community together and his spirit lives on.
"[Wilson] had a smile at all times," said Wager. "Didn't matter who he was with. He did not judge, he did not categorize, and I have watched that spirit grow throughout our community."
Police said the investigation is ongoing and more arrests are possible.
Holland is being held in the Mansfield jail.