Deer Park Police said the teen, Ayden Castaneda, was arrested Wednesday, and a few days later they were able to find out who sold it to him.
Court documents that ABC13 obtained said the student met the seller, Jesus Rodriguez, through a mutual friend.
"We investigate all rumors and all tips," Lt. Chris Brown with the Deer Park Police Department said.
On Wednesday, that tip came in anonymously stating a student at Deer Park High School's south campus had a gun.
Lt. Chris Brown said school resource officers swiftly took action. They arrested 17-year-old Castaneda on the spot.
According to court documents, Castaneda had sent a photo to another student of his gun and that student "perceived it as threatening."
"We started looking at where the gun came from, and after interviews with him and his family, we were able to identify someone who is not related to him that he purchased the firearm from," said Brown.
According to court records, Castaneda used his dad's phone to discuss the deal.
Investigators then discovered a Zelle payment for $399 on Dec. 8 to a number tracing back to Rodriguez.
Brown said tracing a gun's chain of custody when it is sold illegally can be challenging.
"Usually we run into dead ends, but in this case, we were able to find physical evidence," Brown said.
Rodriguez was charged with the unlawful transfer of a weapon to a child.
He's yet to be taken into custody, and according to Brown, he may have been colluding with others.
"We will continue the investigation and see if charges on other people are warranted," Brown said.
According to investigators, Rodriguez drives a 4-door white Chrysler 300. They are asking anyone with info to reach out to them.
ABC13 did speak with Castaneda's father. He had little to say other than his son never brought the gun to school with the intent to hurt anyone.
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