AUSTIN (KXAN) — An 18-year-old charged with capital murder in the death of another 18-year-old met the victim through a phone app, according to an arrest affidavit filed Friday.

In October, police found Andrew Johnson shot inside a crashed car near a McDonald’s off of Mopac near RM 2222 in West Austin.

The arrest affidavit for his alleged killer, Zavien Castilleja, said the two connected on the app Telegram, which Johnson used to sell marijuana. Phone records showed Castilleja talked about robbing Johnson.

“He got in with some bad people, they took advantage of him, and he ended up dead,” said Ryan Dorer, whose son was close friends with Johnson. “Everyone loved Andrew. He was very popular, he was a really sweet/giving kid, he was always trying to do stuff for his friends.”

Sergeant Cody Long with the Hutto Police Department is not working this case, but said app-based drug sales plague police all across Central Texas.

“Especially when it comers to teens, it exposes them to be victimized by more serious offenses, more violent crimes,” he said. “These bad actors are banking on parents not knowing what their kids are doing or who they’re doing it with.”

This kind of app activity can also pose a predicament for parents.

“You want to monitor a teen at first more, and move towards less monitoring based on how they’re handling each level of independence,” said Mandi Meléndez, Owner of Nurture Family Counseling.

Dorer added “It’s hard when they get to 17,18 to know what’s on their phones and what they’re doing, so you have to communicate with them.”